Samacheer Kalvi 12th Chemistry Solutions Chapter 12 Carbonyl Compounds and Carboxylic Acids

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Tamilnadu Samacheer Kalvi 12th Chemistry Solutions Chapter 12 Carbonyl Compounds and Carboxylic Acids

Samacheer Kalvi 12th Chemistry Chapter 12 Carbonyl Compounds and Carboxylic Acids Text Book Evaluation

Samacheer Kalvi 12th Chemistry Carbonyl Compounds and Carboxylic Acids Multiple Choice Questions

Question 1.
The correct structure of the product ‘A’ formed in the reaction

Answer:

Question 2.
The formation of cyanohydrin from acetone is an example of …………..
(a) nucleophilic substitution
(b) electrophilic substitution
(c) electrophilic addition
(d) Nucleophilic addition
Answer:
(d) Nucleophilic addition

Question 3.
Reaction of acetone with one of the following reagents involves nucleophilic addition followed by elimination of water. The reagent is ………….
(a) Grignard reagent
(b) Sn / HCl
(c) hydrazine in presence of slightly acidic solution
(d) hydrocyanic acid
Answer:
(c) hydrazine in presence of slightly acidic solution

Question 4.
In the following reaction,

Product ‘X’ will not give
(a) Tollen’s test
(b) Victor meyer test
(c) Iodoform test
(d) Fehiing solution test
Answer:
(b) Victor meyer test
Hint:

(x) reduces tollens reagent and Fehiing solution and it also answers iodoform test.

Question 5.
In the following reaction,

(a) Formaldehyde
(b) diacetoneammonia
(c) hexamethylene tetra amine
(d) oxime
Answer:
(c) hexamethylene tetra amine
Hint:
X – HCHO
Y – (CH₂)₆ N₄

Question 6.
Predict the product Z in the following series of reactions

i
Answer:

Hint:

Question 7.
Assertion: 2, 2 – dimethyl propanoic acid does not give HVZ reaction.
Reason: 2 – 2, dimethyl propanoic acid does, not have – a hydrogen atom
(a) if both assertion and reason are true and reason is the correct explanation of assertion.
(b) if both assertion and reason are true but reason is not the correct explanation of assertion.
(c) assertion is true but reason is false
(d) both assertion and reason are false
Answer:
(a) if both assertion and reason are true and reason is the correct explanation of assertion.
Hint:

Question 8.
Which of the following represents the correct order of acidity in the given compounds
(a) FCH₂COOH > CH₃COOH > BrCH₂COOH > CICH₂COOH
(b) FCH₂COOH > CICH₂COOH > BrCH₂COOH > CH₃COOH
(c) CH₃COOH > CICH₂COOH > FCH₂COOH > Br – CH₂COOH
(d) ClCH₂COOH > CH₃COOH > BrCH₂COOH > ICH₂COOH
Hint.
– I effect increases the acidity. If electronegativity is high, – I effect is also high.

Question 9.
Benzoic acid

(a) anilinium chloride
(b) O – nitro aniline
(c) benzene diazonium chloride
(d) m – nitro benzoic acid
Answer:
(c) benzene diazonium chloride
Hint:

Question 10.
Ethanoic acid

2 – bromoethanoic acid. This reaction is called ……………
(a) Finkeistein reaction
(b) Haloform reaction
(c) Hell – Volhard – Zelinsky reaction
(d) none of these
Answer:
(c) Hell – Volhard – Zelinsky reaction

Question 11.

(a) acetyl chloride
(b) chlro acetic acid
(c) α – chiorocyano ethanoic acid
(d) none of these
Hint:

Question 12.
Which one of the following reduces tollens reagent ………
(a) formic acid
(b) acetic acid
(c) benzophenone
(d) none of these
Answer:
(a) formic acid
Hint:

Question 13.

Answer:

Hint:

Question 14.
The TUPAC name of
……………………
(a) but – 3 – enoicacid
(b) but 1 – ene – 4 – oicacid
(c) but 2 – ene – 1 – oic acid
(d) but – 3 – ene – 1 – oicacid
Answer:
(a) but – 3 – enoicacid
Hint:

Question 15.
Identify the product formed in the reaction

Answer:

Hint:
Group is reduced to CH₂ – (Wolff – Kishner reduction)

Question 16.
In which case chiral carbon is not generated by reaction with HCN

Answer:

Hint:

Question 17.
Assertion: p – N, N – dimethyl aminobenzaldehyde undergoes benzoin condensation
Reason: The aldehydic (- CHO) group is meta directing
(a) if both assertion and reason are true and reason is the correct explanation of assertion.
(b) if both assertion and reason are true but reason is not the correct explanation of assertion.
(c) assertion is true but reason is false
(d) both assertion and reason are false
Answer:
(b) if both assertion and reason are true but reason is not the correct explanation of assertion.
Hint:

Question 18.
Which one of the following reaction is an example of disproportionation reaction …………….
(a) Aldol condensation
(b) cannizaro reaction
(c) Benzoin condensation
(d) none of these
Answer:
(b) cannizaro reaction
Hint:

Question 19.
Which one of the following undergoes reaction with 50% sodium hydroxide solution to give the corresponding alcohol and acid …………
(a) Phenylmethanal
(b) ethanal
(c) ethanol
(d) methanol
Answer:
(a) Phenylmethanal

Question 20.
The reagent used to distinguish between acetaldehyde and benzaldehyde is ………..
(a) Tollens reagent
(b) Fehling’s solution
(c) 2, 4 – dinitrophenyl hydrazine
(d) semicarbazide
Answer:
(b) Fehling’s solution

Question 21.
Phenyl methanal is reacted with concentrated NaOH to give two products X and Y. X reacts with metallic sodium to liberate hydrogen X and Y are ………….
(a) sodiumbenzoate and phenol
(b) Sodium benzoate and phenyl methanol
(c) phenyl methanol and sodium benzoate
(d) none of these
Answer:
(c) phenyl methanol and sodium benzoate
Hint:

Question 22.
In which of the following reactions new carbon – carbon bond is not formed?
(a) Aldol condensation
(b) Friedel craft reaction
(c) Kolbe’s reaction
(d) Wolf kishner reduction
Answer:
(d) Wolf kishner reduction

Question 23.
An alkene “A” on reaction with O₃ and Zn – H₂O gives propanone and ethanol in equimolar ratio. Addition of HCl to alkene “A” gives “B” as the major product. The structure of product “B” is ……………

Answer:

Hint:

Question 24.
Carboxylic acids have higher boiling points than aldehydes, ketones and even alcohols of comparable molecular mass. It is due to their ………………
(a) more extensive association of carboxylic acid via van der Waals force of attraction
(b) formation of carboxylate ion
(c) formation of intramolecular H – bonding
(d) formation of intermolecular H – bonding
Answer:
(d) formation of intermolecular H – bonding

Question 25.
Of the following, which is the product formed when cyclohexanone undergoes aldol condensation followed by heating?

Answer:

Hint:

II. Answer the following questions.

Question 1.
How is propanoic acid is prepared to start from

an alcohol
an alkyl halide
an alkene

Preparation of propanoic acid from,
Answer:
1. Alcohol:

2. Alkylhalide:

3. Alkene:

Question 2.
A Compound (A) with molecular formula C₂H₃N on acid hydrolysis gives(B) which reacts with thionyichioride to give compound(C). Benzene reacts with compound (C) in presence of anhydrous AlCl₃ to give compound (C). Compound (C) on reduction with gives (D). Identify (A), (B), (C) and D. Write the equations.
Answer:
1. Compound (A) with molecular formula C₂H₃N is methyl cyanide. (CH₃CN)

2. Methyl cyanide (A) on hydrolysis gives acetic acid (B)

3. Acetic acid (B) with thionyl chloride to give acetyl chloride (C)

4. Benzene reacts with acetyl chloride (C) in the presence of anhydrous AlCl₃ to give acetophenone (D)

5. Acetyl chloride (C) on reduced in the presence of Pd / H₂ and Barium sulphate, to gives acetaldehyde (E).

Question 3.
Identify X and Y

Answer:

Question 4.
Identify A, B and C

Answer:

Question 5.
A hydrocarbon A(molecular formula C₈H₁₀) on ozonolysis gives B(C₄H₆O₂ ) only. Compound C( C₃H₅Br) on treatment with magnesium in dry ether gives (D) which on treatment with CO₂ followed by acidification gives (B). Identify A, B, C and D.
Answer:
1. Molecular formula C₈H₁₀ is 1, 2 – di-cyclopropyl ethyne.

2. 1, 2 – dicyclo propyl ethyne (A) on ozonolysis to give cyclo propyl carboxylic acid (B)

3. Compound C₃H₅Br is Bromo cyclopropane (C), which on reacts with Mg in dry ether gives Grignard reagent (D) which on treatment with CO₂ followed by acidification gives cyclopropyl carboxylic acid (B).

Question 6.
Identify A, B, C and D

Answer:

Question 7.
An alkene (A) on ozonolysis gives propanone and aldehyde (E). When (B) is oxidised (C) is obtained. (C) is treated with Br₂ JP gives (D) which on hydrolysis gives (E). When propanone is treated with HCN followed by hydrolysis gives (F). Identify A, B, C, D and E and F.
Answer:
1. 2 – methyl – but – 2 – ene (A) on ozonolysis gives propanone and acetaldehyde (B)

2. Acetaldehyde (B) is oxidised to give acetic acid (C), which on further treated with Br₂ / P give monobromo acetyl bromide (D) which on hydrolysis gives monobromo acetic acid (E).

3. Propanone is treated with HCN followed by hydrolysis to gives 2 – methyl – 2 – hydorxy propanoic acid (F)

Question 8
How will you convert benzaldehyde into the following compounds?

benzophenone
benzoic acid
2 – hydroxyphenylaceticacid.

Answer:
1. conversion of benzaldehyde into benzophenone.

2. conversion of benzaldehyde into benzoic acid.

3. conversion of benzaldehyde into 2 – hydroxy phenyl acetic acid.

Question 9.
What is the action of HCN on

propanone
2, 4 – dichlorobenzaldehyde.

Answer:
1. Propanone reacts with HCN.

2. 2, 4 – dichlorobenzaldehyde reacts with HCN.

Question 10.
A carbonyl compound A having molecular formula C₅H₁₀O forms crystalline precipitate with sodium bisuiphate and gives positive iodoform test. A does not reduce Fehling solution. Identify A.
Answer:
1.

2. Pentan – 2 – one gives positive iodoform test, but it does not reduce Fehling’s solution.

3. Hence carbonyl compound A having molecular formula C₅H₁₀O is pentan – 2 – one.

Question 11.
Write the structure of the major product of the aldol condensation of benzaldehyde with acetone.
Answer:
Step 1:

Step 2:

Step 3:

Step 4:

Question 12.
How are the following conversions effected

propanal into butanone
Hex – 3 – yne into hexan – 3 – one.
phenylmethanal into benzoic acid
phenylmethanal into benzoin

Answer:
1. propanal into butanone

2. Hex – 3 – yne into hexan – 3 – one

3. phenylmethanal into benzoic acid

4. phenyl methanal into benzoin

Question 13.
Complete the following reaction.

Answer:

Overall reaction:

Question 14.
Identify A, B and C

Answer:

Question 15.
When ketones are undergo oxidation, the C – C bond Is cleaved. When a strong oxidising agent is used to oxidise 2, 5 – dimethyl hexan – 3 – one mention the products with their names.
Answer:

Question 16.
How will you convert following conversion?

Acetic acid into acetic anhydride
Methyl acetate into ethyl acetate
Methyl acetate into acetamide
Acetyl chloride into acetophenone
Sodium acetate into ethane
Ethanal into lactic acid
Toluene into benzoic acid
Benzaldehyde into malachite green
Benzaldehyde into Cinnamic acid
Ethyne into acetaldehyde

Answer:
1. Conversion of Acetic acid into acetic anhydride

2. Conversion of Methyl cyanate into acetamide.

3. Conversion of Methyl cyanate into acetamide.

4. Conversion of Acetyl chloride into acetophenone.

5. Conversion of Sodium acetate into ethane.

6. Conversion of Ethanal into lactic acid.

7. Conversion of Toluene into benzoic acid.

8. Conversion of Benzaldehyde into malachite green.

9. Conversion of benzaldehyde into cinnamic acid.

10. Conversion of Ethyne into acetaldehyde.

Samacheer Kalvi 12th Chemistry Carbonyl Compounds and Carboxylic Acids Evaluate yoursel

Question 1.
Write the IUPAC name for the following compound.

Answer:

Question 2.
Write all possible structural isomers and position isomers for the ketone represented by the molecular formula C₅H₁₀O.
Answer:
Molecular formula C₅H₁₀O exhibits following possible ketone structural isomers and position isomers.

Question 3.
What happens when the following alkenes are subjected to reductive ozonolysis.

propene
1 – Butene
Isobutylene

Answer:
1. propene

2. 1 – Butene

3. Isobutylene

Question 4.
What happens when n-propyl benzene is oxidised using H⁺ / KMnO₄?
Answer:
When n – propyl benzene is oxidised with H⁺ / KMnO₄ to gives benzoic acid.

Question 5.
How will you prepare benzoic acid using Crignard reagent.
Answer:
Preparation of benzoic acid using Grignard reagent:

Question 6.
Why acid anhydride are preferred to acyl chloride for carrying out acylation reactions?
Answer:

Since acyl chlorides are more reactive, their reactions are very fast and difficult to control.
Acid anhydrides are less reactive than acyl chlroides and their reactions can be easily controlled.
Hence acid anhydrides are preferred to acyl chlorides for carrying out acylation reactions.

Samacheer Kalvi 12th Chemistry Carbonyl Compounds and Carboxylic Acids Additional Questions

Samacheer Kalvi 12th Chemistry Carbonyl Compounds and Carboxylic Acids 1 Mark Questions and Answers

I. Choose the best answer.

Question 1.
Which one of the following aldehyde is derived from vitamin B, function as a co – enzyme?
(a) Pyridoxal
(b) Formaldehyde
(c) Ethanal
(d) Propanal
Answer:
(a) Pyridoxal

Question 2.
Which one of the following is used in the manufacture of Bakelite?
(a) Methanal
(b) Ethanal
(c) Phenyl methanal
(d) Butanal
Answer:
(a) Methanal

Question 3.
Which is used as a drug to reduce fever?
(a) Diethyl ether
(b) Acetone
(c) Acetophenone
(d) Paracetamol
Answer:
(d) Paracetamol

Question 4.
The IUPAC name of Acrolein is
(a) Prop – 2 – enal
(b) Propanal
(c) Ethenal
(d) 1 – butanal
Answer:
(a) Prop – 2 – enal

Question 5.
The IUPAC name of crotanaldehyde CH₃ – CH = CH – CHO is …………….
(a) Prop – 2 – enal
(b) But – 2 – enal
(c) Ethenal
(d) Phenyl methanal
Answer:
(b) But – 2 – enal

Question 6.
The IUPAC name of is
…………………..
(a) Glyceraldehyde
(b) Acrolein
(c) 2, 3 – dihydroxy propanal
(d) Butanal
Answer:
(c) 2, 3 – dihydroxy propanal

Question 7.
Which one of the following is called Mesityl oxide?

Answer:

Question 8.
Which one of the following is called 3 – oxopentanal?

Answer:

Question 9.
Which one of the following is names as 3 – methyl cyclopentanone?

Answer:

Question 10.
Which one of the following is the hybridised state of C atoms in carbonyl carbon?
(a) sp
(b) sp³d
(c) sp³
(d) sp²
Answer:
(d) sp²

Question 11.
Which of the following reagent is used to get aldehyde from alcohol by oxidation method?
(a) Na₂Cr₂O₇
(b) KMnO₄
(c) PCC
(d) LiAlH₄
Answer:
(c) PCC

Question 12.
The product formed when but – 2 – ene is on ozonolysis is ………….
(a) Propanone
(b) Methanal
(ç) Ethanal
(d) Butanal
Answer:
(ç) Ethanal

Question 13.
Which one of the following should be ozonolysed to get a mixture of ethanal and propanone?
(a) Propene
(b) But – 2 – ene
(c) Ethylene
(d) 2 – methyl – but – 2 – ene
Answer:
(d) 2 – methyl – but – 2 – ene

Question 14.
The products formed when propene is ozonolysed are …………….
(a) HCHO + CH₃CHO
(b) CH₃CHO
(c) HCOOH + CH₃COOH
(d) CH₃COCH₃
Answer:
(a) HCHO + CH₃CHO

Question 15.
Identify the products formed when But- 1-ene undergoes reductive ozonolysis?
(a) HCHO + CH₃CHO
(b) HCHO + CH₃CH₂CHO
(c) CH₃COCH₃ + CH₃CHO
(d) HCHO + CH₃COCH₃
Answer:
(b) HCHO + CH₃CH₂CHO

Question 16.
Which one of the following should be subjected to reductive ozonolysis to get only formal dehyde?
(a) CH ≡ CH
(b) CH₃ – CH = CH₂
(c) CH₂ = CH₂
(d) CH₃ – CH₃
Answer:
(c) CH₂ = CH₂

Question 17.
What are the products formed when Isobutylene is subjected to ozonolysis?
(a) HCHO + CH₃CHO
(b) CH₃COCH₃ + HCHO
(c) CH₃CHO + CH₃COCH
(d) CH₃COCH₃ + CH₃CH₂CHO
Answer:
(b) CH₃COCH₃ + HCHO

Question 18.
Which one of the following is formed when acetylene is hydrolysed in the presence of HgSO₄ and H₂SO₄?
(a) Ethanal
(b) Ethylene
(c) Ethane
(d) Ethanol
Answer:
(d) Ethanol

Question 19.
Hydrolysis of prop – 1 – yne in the presence of HgSO₄ and H₂SO₄ gives ……………

Answer:

Question 20.

Answer:
(a) CaCO₃ + H₂
(b) CO₂ + H₂O + Ca
(c) HCHO + CaCO₃
(d) CO + H₂O + Ca(OH)₂
Answer:
(c) HCHO + CaCO₃

Question 21.
Calciwn acetate on dry distillation gives …………
(a) Acetic acid
(b) Propanone
(c) Ethanol
(d) Propanal
Answer:
(b) Propanone

Question 22.
Which of the following calcium salts are required to get ethanal by dry distillation process?

Answer:

Question 23.
The conversion of acetyl chloride to acetaldehyde by the action of Pd/BaSO₄ is called ………………..
(a) Perkin’s reaction
(b) Stephens reaction
(c) Clemmenoon reduction
(d) Rosenmund reduction
Answer:
(d) Rosenmund reduction

Question 24.
Which of the following cannot be prepared by Rosenmund reduction method?
(a) Acetaldehyde
(b) Formaldehyde
(c) Ketone
(d) Both b & c
Answer:
(d) Both b & c

Question 25.
In Rosenmunds reduction, the action of BaSO₄ is …………….
(a) Promoter
(b) Catalyst poison
(c) Positive catalyst
(d) Negative catalyst
Answer:
(b) Catalyst poison

Question 26.
Which one of the following is an intermediate product in Stephen’s reaction?
(a) Amines
(b) Amides
(c) Imines
(d) Amino acid
Answer:
(c) Imines

Question 27.
Which one of the following is used as selective reducing agent in the conversion of cyanide to aldehyde?
(a) Raney Ni
(b) LiAlH₄
(c) SnCl₂ / HCl
(d) DIBAL – H
Answer:
(d) DIBAL – H

Question 28.
Identify the product formed when benzaldehyde reacts with chromyl chloride?
(a) Benzoic acid
(b) Benzaldehyde
(c) Phenyl methanol
(d) Phenol
Answer:
(b) Benzaldehyde

Question 29.
The conversion reaction of Benzene to Benzaldehyde is known as ……………..
(a) Rosenmund reduction
(b) Stephen reduction
(c) Gattermann koch reaction
(d) Friedel – crafts reaction
Answer:
(c) Gattermann koch reaction

Question 30.
Which one of the following is used to convert acetyl chloride to acetone?
(a) CdCl₂
(b) CrO₂CI₂
(c) Cu₂CI₂
(d) NaCl
Answer:
(a) CdCl₂

Question 31.
Which one of the following is the best method to prepare alkyl aryl ketone and diaryl ketones?
(a) Stephen reaction
(b) Knoevengal reaction
(c) Ciemmenson reduction
(d) Friedel crafts reaction
Answer:
(d) Friedel crafts reaction

Question 32.
The product formed when Benzoyl chloride reacts with benzene is ………….
(a) Benzyl benzoate
(b) Benzophenone
(c) Benzyl chloride
(d) Benzyl alcohol
Answer:
(b) Benzophenone

Question 33.
Which one of the following is used as catalyst in Friedel Crafts reaction?
(a) Anhydrous ZnCl₂
(b) Anhydrous CuCl₂
(c) Anhydrous AlCl₃
(d) Androus CaCl₂
Answer:
(c) Anhydrous AlCl₃

Question 34.
During nucleophilic addition reaction, the hybridisation of carbon changes from
(a) sp² to sp³
(b) sp³ to sp²
(c) sp to sp³
(d) dsp² to sp³
Answer:
(a) sp² to sp³

Question 35.
Which one of the following is formed as a product when ethanal is treated with 2 equivalent of methanol?
(a) 1, 1 – dimethoxy methane
(b) 1 ,2 – dimethoxy ethane
(c) 1, 1 – dimethoxy ethane
(d) 1, 1 – diethoxy ethane
Answer:
(c) 1, 1 – dimethoxy ethane

Question 36.
Which aldehyde does not give aldimine with etheral ammonia solution?

Answer:

Question 37.
Identify the product formed when acetaldehyde reacts with ammonia?

Answer:

Question 38.
Which one of the following is formed when methanal reacts with ammonia?
(a) Tetramethylene hexamine
(b) Hexamethylene tetramine
(c) Formaldehyde ammonia
(d) Aldimine
Answer:
(b) Hexamethylene tetramine

Question 39.
Which one of the following is used as, an urinary antiseptic?
(a) Urotropine
(b) Urea formaldehyde
(c) Formalin
(d) Aldimm
Answer:
(a) Urotropine

Question 40.
Which one of the reactions gives an explosive RDX?
(a) Nitration of phenol
(b) Nitration of glycol
(c) Nitration of urotropine
(d) Nitration of glycerol
Answer:
(c) Nitration of urotropine

Question 41.
Which one of the following is called hydrobenzamide?

Answer:

Question 42.
Which one of the following is formed when benzaldehyde reacts with ammonia?
(a) Benzalamine
(b) Benzylamine
(c) Hydrobenzarnide
(d) Benzarnide
Answer:
(c) Hydrobenzarnide

Question 43.
Which rule governes the oxidation of unsymmetrical ketone?
(a) Markovnikoff’s rule
(b) Popoff s rule
(c) Antimarkovnikoff s rule
(d) Hund’s rule
Answer:
(b) Popoff s rule

Question 44.
What are the products formed when 2-butanonc is oxidised by conc – HNO₃?

Answer:

Question 45.

In this reaction A and B are …………

Answer:

Question 46.
Name the product formed Acetaldehyde reacts with Zinc amalgam and conc.HCl?
(a) Propane
(b) Ethane
(c) Ethene
(d) Ethanal
Answer:
(b) Ethane

Question 47.
The reagent used in the Conversion of group into – CH₂ – group is …………..
(a) Zn + Hg / HCl
(b) NH₂ – NH₂ + C₂H₅ONa
(c) mg / Hg / H₂O
(d) either (a) or (b)
Answer:
(d) either (a) or (b)

Question 48.
The product formed when Acetone is subjected to Clemmenson reduction is ……………..
(a) Acetic acid
(b) Propanoic acid
(c) Propane
(d) Propanal
Answer:
(c) Propane

Question 49.
Which one of the following is formed when acetone is treated with magnesium amalgam and water?
(a) Pinacol
(b) Acetyl acetone
(c) Aceto acetic ester
(d) 1 ,2 – dimethyl butane 1, 2 – diol
Answer:
(a) Pinacol

Question 50.
Which one of the following does not undergo halo form reaction?

Answer:

Question 51.
Which one of the following undergoes halo form reaction?
(a) HCHO
(b) C₆H₅CHO
(c) CH₃CHO
(d) CH₃ – CH₂ – CH₂OH
Answer:
(c) CH₃CHO

Question 52.
Which one of the following is formed when acetaldehyde is warmed with dilute NaOH?
(a) But – 2 – enal
(b) Butan – 1 – al
(c) 3 – hydroxy butanal
(d) 2 – hydroxybutanoic acid
Answer:
(c) 3 – hydroxy butanal

Question 53.
The IUPAC naine of Acetaldol is ……………
(a) 3 – hydroxy butanal
(b) Aldol
(c) 2 – hydroxy butanal
(d) Butanal
Answer:
(a) 3 – hydroxy butanal

Question 54.
Which one of the following is formed when benzaldehyde reacts with acetaldehyde?
(a) Cinnamic acid
(b) Cinnamaldehyde
(c) Benzylidene acetone
(d) 3 – hydroxy propanal
Answer:
(b) Cinnamaldehyde

Question 55.
The crossed aldol condensation product of the reaction between Formaldehyde and Acetaldehyde is ………………
(a) 3 – hydroxy propanol
(b) 3 – hydroxy propanal
(c) 2 – hydroxy butanal
(d) 3 – hydroxy butanal
Answer:
(b) 3 – hydroxy propanal

Question 56.
The reaction of benzaldehyde with 50% NaOH is called …………..
(a) Benzoin condensation
(b) Claisen – schmidt reaction
(c) Perkin’s reaction
(d) Cannizaro reaction
Answer:
(d) Cannizaro reaction

Question 57.
The reaction of phenyl methanal and ethanal in the presence of dilute NaOH is known as ……………..
(a) Cannizaro reaction
(b) Aldol condensation
(c) Claisen – schmidt condensation
(d) Perkin’s reaction
Answer:
(c) Claisen – schmidt condensation

Question 58.
What is the second step in Cannizaro reaction mechanism?
(a) Attack of OH^– on carbonyl carbon
(b) Acid base reaction
(c) Protonation of carbonyl oxygen
(d) Hydride ion transfer
Answer:
(d) Hydride ion transfer

Question 59.
The first step take place in Cannizaro reaction mechanism is ……………..
(a) Aftack of OH^– on carbonyl carbon
(b) Protonation of carbonyl oxygen
(c) Acid base reaction
(d) Hydride ion transfer
Answer:
(a) Aftack of OH^– on carbonyl carbon

Question 60.
Which one of the following is formed when benzaldehyde reacts with alcoholic KOH?
(a) Benzyl alcohol
(b) Potassium henzoate
(c) Benzoin
(d) Benzoic acid
Answer:
(c) Benzoin

Question 61.
What is the name of the reaction of alcoholic KOH with Benzaldehyde’?
(a) Cannizaro reaction
(c) Benzoin condensation
(b) Perkin’s reaction
(d) Aldol condensation
Answer:
(c) Benzoin condensation

Question 62.
Which one of the following is formed when benzaldehyde reacts with acetic anhydride?
(a) Cinnamaldehyde + Acetaldehyde
(b) Cinnamic acid + Acetic acid
(c) Benzyl alcohol + Benzoic acid
(d) Benzal aniline + Acetic acid
Answer:
(b) Cinnamic acid + Acetic acid

Question 63.
What is the name of the reaction between Benzaldehyde and acetic anhydride?
(a) Peridn’s reaction
(b) Knoerenagal reaction
(c) Cannizaro reaction
(d) Kolbe’s reaction
Answer:
(a) Peridn’s reaction

Question 64.
What are the reagents required to prepare Benzal aniline (or) Schiff’s base?
(a) Benzyl amine + Ammonia
(b) Benzal amine + Ammonia
(c) Benzaldehyde + Aniline
(d) Phenol + Aniline
Answer:
(c) Benzaldehyde + Aniline

Question 65.
Which one of the following is the formula of Schiff’ s base’?
(a) C₆H₅ – NH NH₂
(b) C₆H₅ CH = N – C₆H₅
(b) Perkin’s reaction
(d) Aldol condensation
Answer:
(b) C₆H₅ CH = N – C₆H₅

Question 66.
Which one of the following is used as a catalyst in Knoevenagal reaction?
(a) Pyrimidine
(b) Pyridine
(c) PCC
(d) CdCl₂
Answer:
(b) Pyridine

Question 67.
Which one is formed when Benzaldehyde reacts with Malonic acid in the presence of Pyridine?
(a) Cinnamaldehyde
(b) Benzoin
(c) Hydrobenzamide
(d) Cinnamic acid
Answer:
(d) Cinnamic acid

Question 68.
Name the product formed when Benzaldehyde reacts with N,N – dimethyl aniline in the presence of conc.H₂SO₄?
(a) Cinnamic acid
(b) Skiffs base
(c) Malachite green dye
(d) p – hydroxy azodye
Answer:
(c) Malachite green dye

Question 69.
Identify the product formed when benzaldehyde reacts with chlorine in the presence of conc.FeCl₃?
(a) m – chlorobenzaldehyde
(b) O – chlorobenzaldehyde
(c) p – chiorobenzaldehyde
(d) Benzoyl chloride
Answer:
(a) m – chlorobenzaldehyde

Question 70.
Identify the product formed when benzaldehyde reacts with chlorine in the absence of catalyst?
(a) p – chiorobenzaldehyde
(b) O – chiorobenzaldehyde
(c) Benzoyl chloride
(d) m – chlorobenzaldehyde
Answer:
(c) Benzoyl chloride

Question 71.
Which one of the following is used to test ketones?
(a) lodoform test
(b) Tollen’s reagent test
(c) Fehling’s solution test
(d) Benedict’s solution test
Answer:
(a) lodoform test

Question 72.
Which one of the following is not used to identify aldehydes?
(a) Benedict’s solution test
(b) Fehling’s solution test
(c) Dye test
(d) Tollen’s reagent test
Answer:
(c) Dye test

Question 73.
What is the colour change take place when Fehling’s solution is added to an aldehyde?
(a) Red to blue
(b) Blue to red
(c) Red to green
(d) Green to blue
Answer:
(b) Blue to red

Question 74.
Which one of the following is used for preserving biological specimens?
(a) Urotropine
(b) Formalin
(c) Schiff’s base
(d) Benzoin
Answer:
(b) Formalin

Question 75.
Which one of the following is formed when phenol is heated with formalin?
(a) Bakelite
(b) PVC
(c) Polyurethane
(d) Polyester
Answer:
(a) Bakelite

Question 76.
RDX is otherwise named as …………….
(a) Cyclonite
(b) Cyclohexane
(c) 1, 4 – dione
(d) Cyclohexanol
Answer:
(a) Cyclonite

Question 77.
Which one of the following is used as a hypnotic?
(a) Acetaldehyde
(b) Formalin
(c) Paraldehyde
(d) Formaldehyde
Answer:
(c) Paraldehyde

Question 78.
Which one of the following is used in silvering of mirrors?
(a) Paraldehyde
(b) Benzaldehyde
(c) Acetone
(d) Acetaldehyde
Answer:
(d) Acetaldehyde

Question 79.
Which one of the following is used in the manufacture of smokeless powder (cordite)?
(a) Acetone
(b) Acetaldehyde
(c) Acetic acid
(d) Formaldehyde
Answer:
(a) Acetone

Question 80.
Which one of the following is used as nail polish remover?
(a) CH₃CHO
(b) HCHO
(c) CH₃COCH₃
(d) C₆H₅COCH₃
Answer:
(c) CH₃COCH₃

Question 81.
Which is used in the manufacture of thermosoftening plastic perspex?
(a) Acetaldehyde
(b) Formaldehyde
(c) Acetone
(d) Acetophenone
Answer:
(c) Acetone

Question 82.
Which of the following is called hyphone?

Answer:

Question 83.
Which of the following is used in the preparation of benzhydrol drop?
(a) Benzaldehyde
(b) Benzophenone
(c) Acetophenone
(d) Benzoin
Answer:
(b) Benzophenone

Question 84.
Consider the following statements.
(i) Terminal olefins gives Formaldehyde as one of the product
(ii) Oxidation of alcohols using pcc yield carboxylic acids
(iii) Catalytic dehydrogenation of alcohols give either aldehyde or ketone.
Which of the above statement is/are not correct?
(a) (ii) only
(b) (i) & (iii)
(c) (ii) & (iii)
(d) (ii) only
Answer:
(a) (ii) only

Question 86.
Consider the following statements:
(i) Formaldehyde is a gas at room temperature and acetaldehyde is a volatile liquid.
(ii) The oxidation of symmetrical ketones is governed by Popoti’s rule.
(iii) Aliphatic aldehyde react with primary amines in the presence of base gives Schiff’s base.
Which of the above statement is/are not correct?
(a) (i) only
(b) (ii) only
(c) (ii) & (iii)
(d) (i) & (ii)
Answer:
(c) (ii) & (iii)

Question 87.
The JUPAC name of is
(a) Benzene carboxylic acid
(b) Benzoic acid
(c) 2 – phenyl ethanoic acid
(d) 2 – phenyl acetic acid
Answer:
(c) 2 – phenyl ethanoic acid

Question 88.
The formula of malonic acid is …………

Answer:

Question 89.
The IUPAC name of HOOC – (CH₂)₄ – COOH is ………………
(a) Adipic acid
(b) Butane dioic acid
(c) Hexane diolc acid
(d) Glutaric acid
Answer:
(c) Hexane diolc acid

Question 90.
Which one of the following is the formula of Succinic acid?
(a) HOOC – CH₂ – COOH
(b) HOOC – (CH₂)₂ – COOH
(c) HOOC – (CH₂)₄ – COOH
(d) HOOC – (CH)₃ – COOH
Answer:
(b) HOOC – (CH₂)₂ – COOH

Question 91.
Consider the following statements.
(i) In – COOH group, the centre carbon atom and both the oxygen atoms are in sp³ hybridisation.
(ii) RCOOH can be represented as a resonance hybrid of two canonical structures.
(iii) Carboxylic carbon is less electrophilic than carbonyl carbon because of the reasonan structure.
Which of the above statement is/are correct?
(a) (iii) only
(b) (ii) only
(c) (i) only
(d) (i) & (ii)
Answer:
(b) (ii) only

Question 92.
Which one of the following reacts with methyl magnesium iodide followed by acid hydrolysis yield acetic acid?
(a) Solid CO₂
(b) HCHO
(c) CH₃CHO
(d) CH₃CN
Answer:
(a) Solid CO₂

Question 93.
Which one of the following acid cannot be prepared from grignaid reagent by the action of dry ice?
(a) CH₃COOH
(b) C₆H₅COOH
(c) CH₃ – CH₂COOH
(d) HCOOH
Answer:
(d) HCOOH

Question 94.
Which one of the following is formed as a product when Benzoic anhydride is hydrolysed?
(a) Benzoin
(b) Benzoic acid
(c) Benzyl alcohol
(d) Benzaldehyde
Answer:
(b) Benzoic acid

Question 95.
Consider the following statements.
(i) Carboxylic acids have higher boiling point than aldehyde and ketone due to the association of carboxylic acid.
(ii) Vinegar is 60 to 80% solution of acetic acid in water
(iii) Higher carboxylic acids are insoluble in water due to increased hydrophobic interaction of hydrocarbon part.
Which of the above statement is/are not correct’?
(a) (iii) only
(b) (ii) only
(c) (i) only
(d) (i) & (iii)
Answer:
(b) (ii) only

Question 96.
Which one of the following is formed when ethanoic acid is treated with HI and Red phosphorous?
(a) Ethane
(b) Ethene
(c) Ethyne
(d) Methane
Answer:
(a) Ethane

Question 97.
What will be the product formed when sodium acetate is treated with sodalime?
(a) C₂H₆
(b) CH₄
(c) CH₃COOH
(d) (CH₃CO)₂O
Answer:
(b) CH₄

Question 98.
The reaction of electrolysis of sodium acetate to form ethane is known as ………………..
(a) Kolbe’s electrolytic decarboxylation
(b) Perkin’s reaction
(c) Clemmenson reaction
(d) Cannizaro reaction
Answer:
(a) Kolbe’s electrolytic decarboxylation

Question 99.
Sodium formate solution on electrolysis gives at anode.
(a) Methane + CO₂
(b) Ethane + CO₂
(c) H₂ + CO₂
(d) Formic acid
Answer:
(c) H₂ + CO₂

Question 100.
Which one of the following is formed when acetic acid is heated with phosphorous pentoxide?
(a) CH₃COCH₃
(b) CH₃CONH₂
(c) CH₄
(d) (CH₃CO)₂O
Answer:
(d) (CH₃CO)₂O

Question 101.
The reaction of acetic acid with Cl₂ and red phosphorous is named as ………………
(a) Kolbe’s reaction
(b) Reimer – Tiemann reaction
(c) HeII – volhard – zelinsky reaction
(d) Knoevenagal reaction
Answer:
(c) HeII – volhard – zelinsky reaction

Question 102.
Which one of the following does not undergo friedel crafts reaction?

Answer:

Question 103.
Which one of the following can act as a reducing agent?
(a) C₆H₅COOH
(b) HCOOH
(c) CH₃COOH
(d) CH₃ – CH₂COOH
Answer:
(b) HCOOH

Question 104.
Consider the following statements.
(i) Carboxylic acids turn red litmus blue.
(ii) Carboxylic acids give brisk efferrescence with NaHCO3
(iii) Carboxylic acid is warmed with alcohol and conc. H₂SO₄ gives fruity odour ester.
Which of the above statement is/are not correct?
(a) (i) only
(b) (ii) only
(c) (iii) only
(d) (i) & (iii)
Answer:
(a) (i) only

Question 105.
Which is one the correct order of strength of carboxylic acid?

Answer:

Question 106.
The correct increasing order acid strength of carboxylic acid is …………
(a) F – CH₂ – COOH > I – CH₂ – COOH > CI – CH₂ – COOH > Br – CH₂ – COOH
(b) Br – CH₂ – COOH > F – CH₂COOH > I – CH₂COOH > Cl – CH₂ – COOH
(c) F – CH₂ – COOH > CI – CH₂COOH > Br – CH₂COOH > I – CH₂COOH
(d) Br – CH₂ – COOH > CI – CH₂ – COOH > I – CH₂COOH > F – CH₂COOH
Answer:
(c) F – CH₂ – COOH > CI – CH₂COOH > Br – CH₂COOH > I – CH₂COOH

Question 107.
The increasing order of acid strength is ………….
(a) CH₃COOH > CI₂CHCOOH > CCI₃CCOOH > ClCH₂COOH
(b) CI₃CCOOH > CI₂CH COOH > CICH₂COOH > CH₃COOH
(c) CH₂COOH < CI₂CH COOH < CCl₃CCOOH < ClCH₂COOH
(a) Cl₂CH – COOH < CCI₃COOH < ClCH₂COOH < CH₃COOH
Answer:
(b) CI₃CCOOH > CI₂CH COOH > CICH₂COOH > CH₃COOH

Question 108.
The relative acidities of various organic compounds are ……………
(a) RCOOH > ArOH > H₂O > ROH > RC ≡ CH
(b)RCCH > ArOH > ROH > H₂O > RCOOH
(c) ROH > R ≡ CH > ArOH > RCOOH > H₂O
(d) H₂O > ROH > RCOOH > ArOH > RC ≡ CH
Answer:
(a) RCOOH > ArOH > H₂O > ROH > RC ≡ CH

Question 109.
The correct order of the basicity of the leaving group is …………..

Answer:

Question 110.
The conversion of Ethyl acetate to propyl acetate by the action of propyl alcohol is named as
(a) Esterification
(b) Transesterfication
(c) Acid hydrolysis of ester
(d) Alkaline hydrolysis of ester
Answer:
(b) Transesterfication

Question 111.
Ethyl acetate undergoes self condensation in the presence of strong base to give ………………..
(a) Ethyl aceto acetate + Ethanol
(b) Ethyl aceto acetate + Acetic acid
(c) Ethyl aceto propionate + propanol
(d) Ethyl ethanoate + Ethanoic acid
Answer:
(a) Ethyl aceto acetate + Ethanol

Question 112.
Methyl cyanide on acid hydrolysis gives
(a) Acetyl chloride
(b) Acetic acid
(c) Acetamide
(d) Acetic anhydride
Answer:
(c) Acetamide

Question 113.
Which one of the following is the product formed when acetamide is treated with P₂O₅?
(a) Acetonitrile
(b) Methylamine
(c) Ethyl cyanide
(d) Methanamine
Answer:
(a) Acetonitrile

Question 114.
Identify the product formed when acetamide reacts with LiAIH₄?
(a) Methyl amine
(b) Aceto nitrite
(c) Ethyl amine
(d) Ethylcyanide
Answer:
(c) Ethyl amine

Question 115.
Which one of the following is used as a medicine in the treatment of gout?
(a) CH₃COOH
(b) C₆H₅COOH
(c) CH₃CONH₂
(d) HCOOH
Answer:
(d) HCOOH

Question 116.
Which one of the following is used as a coagulating agent for rubber latex?
(a) Ethanoyl chloride
(b) Butanoic acid
(c) Methanoic acid
(d) Benzoic acid
Answer:
(c) Methanoic acid

Question 117.
Which one of the following is used as food preservative?
(a) Sodium formate
(b) Sodium acetate
(c) Sodium benzoate
(d) Acetamide
Answer:
(c) Sodium benzoate

Question 118.
Which one of the following is used in detection and estimation of – OH and – NH₂ group in organic compounds?
(a) Acetic anhydride
(b) Acetyl chloride
(c) Acetamide
(d) Ethyl acetate
Answer:
(b) Acetyl chloride

Question 119.
Which one of the following is used in the preparation of medicine like aspirin and phenacetin?
(a) Acetyl chloride
(b) Acetic acid
(c) Acetamide
(d) Acetic anhydride
Answer:
(d) Acetic anhydride

Question 120.
Which one of the following is used in the preparation of Artificial fruit essences?
(a) Ethanoic acid
(b) Acetamide
(c) Ethyl acetate
(d) Acetic anhydride
Answer:
(c) Ethyl acetate

Question 121.
Acetone and acetaldehyde are differentiated by ………….
(a) NaOH + I²
(b) Ag(NH₃)₂⁺ (Tollens’s reagent)
(c) I²
(d) NaOH + NH₃
Answer:
(b) Ag(NH₃)₂⁺ (Tollens’s reagent)

Question 122.
The most suitable reagent for the conversion of is R – CH₂OH → RCHO …………..
(a) KMnO₄
(b) K₂Cr₂O₇
(c) CrO₃
(d) Pcc
Answer:
(d) Pcc

Question 123.
Which of the following will not give iodoform test?
(a) Isopropyl alcohol
(b) Ethanol
(c) Eth anal
(d) Benzyl alcohol
Answer:
(d) Benzyl alcohol

Question 124.
Products of the following reaction …….

(a) CH₃CHO + CH₃CH = CHO
(b) CH₃COOH + CH₃CH₂CHO
(c) CH₃COOH + HOOCCH₂CH₃
(d) CH₃COOH + CO₂
Answer:
(b) CH₃COOH + CH₃CH₂CHO

Question 125.
Identify the reagents X and Y are ………………

(a) X = MgCl₂ Y = CH₃CH = CH₂
(b) X = CH₃ MgCI Y = C₆H₅COCH₃
(c) X = CH₃ MgCI Y = (CH₃)₃C – OH
(d) X = C₆H₅ MgCI Y = (CH₃)₃C – OH
Answer:
(c) X = CH₃ MgCI Y = (CH₃)₃C – OH

Question 126.
Reduction of > C = O to – CH₂ can be carried out with ……………
(a) Ni
(b) Na/C₂H₅OH
(c) NH₂ – NH₂ + C₂HONa
(d) LiAIH₄
Answer:
(c) NH₂ – NH₂ + C₂HONa

Question 127.
Which of the following is incorrect?
(a) FeCl₃ is used in the detection of phenols
(b) Fehlings solution is used in the detection of aldehyde
(c) Tollen’s reagent is used in the detection of unsaturation
(d) NaHSO₃ is used in the detection of carbonyl compounds
Answer:
(c) Tollen’s reagent is used in the detection of unsaturation

Question 128.
Which of the following products is formed when Benzaldehyde is treated with CH₃MgBr and the addition product so obtained is subjected to acid hydrolysis?
(a) Secondary alcohol
(b) Primary alcohol
(c) Phenol
(d) Tertiary alcohol
Answer:
(a) Secondary alcohol

Question 129.
The reagent used to distinguish formaldehyde and acetaldehyde is …………..
(a) Tollen’s reagent
(b) Fehling’s solution
(c) Schiff’s reagent
(d) Caustic soda solution
Answer:
(d) Caustic soda solution

Question 130.
Which of the followìng will not give halo form test?
(a) Ethanal
(b) Ethanol
(c) Propan – 2 – one
(d) Pentan – 3 – one
Answer:
(d) Pentan – 3 – one

Question 131.
Which of the following does not turn schiff’s reagent to pink?
(a) Formaldehyde
(b) Benzaldehyde
(c) Acetone
(d) Acetaldehyde
Answer:
(c) Acetone

Question 132.
Which will not give acetamide on reaction with ammonia?
(a) Acetic acid
(b) Acetyl chloride
(c) Acetic anhydride
(d) methyl formate
Answer:
(d) methyl formate

Question 133.
The addition of HCN to carbonyl compounds is an example of ………….. reaction.
(a) N ucleophilic substitution
(b) Electrophil ic addition
(c) Nucleophilic addition
(d) Electrophilic substitution
Answer:
(c) Nucleophilic addition

Question 134.
Cinnamic acid is formed when C₆H₅CHO condenses with (CH₃CO)₂O in the presence of ……………
(a) Conc.H₂SO₄
(b) CH₃COONa
(c) Na metal
(d) Anhydrous ZnCI₂
Answer:
(b) CH₃COONa

Question 135.
The molecular formula of Urotropine is …………..
(a) (CH₂)₆N₄
(b) (CH₂)₄N₆
(c) (CH₂)₂N₂
(d) (CH₂)₆N₆
Answer:
(a) (CH₂)₆N₄

Question 136.
Bakelite is a thermosetting plastic produced by …………….
(a) HCHO + C₆H₅CH₂OH
(b) HCHO + C₆H₅OH
(c) CH₃CHO + C₆H₅OH
(d) HCHO + CH₃COCH₃
Answer:
(b) HCHO + C₆H₅OH

Question 137.
Aldehydes and ketones are reduced to hydrocarbon by the action of ………….
(a) LiAlH₄
(b) H₂ / Pd + BaSO₄
(c) Na + Hg/HCI
(d) NH₂ – NH₂ / C₂H₅ONa
Answer:
(d) NH₂ – NH₂ / C₂H₅ONa

Question 138.
What is the name of the reaction when benzaldehyde changes into Benzyl alcohol?
(a) Friedel – crafts reaction
(b) Kolbe’s reaction
(c) Cannizaro reaction
(d) Wurtz reaction
Answer:
(c) Cannizaro reaction

Question 139.
Aldehyde turns pink with …………..
(a) Benedict solution
(b) Schiff ‘s base
(c) Fehiing solution
(d) Tollen’s reagent
Answer:
(b) Schiff ‘s base

Question 140.
Which of the following would undergo aldol condensation?

Answer:

Question 141.
Which one of the following undergoes reaction with 50% NaOH solution to give the corresponding alcohol and acid?
(a) Butanal
(b) Phenyl methanal
(c) Phenol
(d) Ethanal
Answer:
(b) Phenyl methanal

Question 142.
Hexa methylene tetramine is used as ………………
(a) analgesic
(b) antipyretic
(c) Urinary antiseptic
(d) all of these
Answer:
(c) Urinary antiseptic

Question 143.
The compound which gives acetone on ozonolysis is …………
(a) CH₃ – CH = CH – CH₃
(b) (CH₃)₂C = C(CH₃)₂
(c) C₆H₅CH = CH₂
(d) CH₃ – CH = CH₂
Answer:
(b) (CH₃)₂C = C(CH₃)₂

Question 144.
Predict the product X in the sequence of the reaction

Answer:

Question 145.
From which of the following, tertiary butyl alcohol is obtained by the action of methyl magnesium iodide?
(a) HCHO
(b) CH₃COCH₃
(c) CH₃CHO
(d) CO₂
Answer:
(b) CH₃COCH₃

Question 146.
Tdentifý the product “C” in the sequence of the reaction.

(a) CH₃CH₂NH₂
(b) CH₃CH₂OH
(c) CH₂ = CH₂
(d) CH₃CHO
Answer:
(c) CH₂ = CH₂

Question 147.
O₃ reacts with CH₂ = CH₂ to form ozonide. On hydrolysis it forms …………….

Answer:

Question 148.
Ethyne on reaction with water in the presence of HgSO₄ and H₂SO₄ gives …………….
(a) Propanone
(b) Ethanal
(c) Ethane
(d) Ethanol
Answer:
(b) Ethanal

Question 149.
Which of the aldehyde is most reactive?
(a) C₆H₅CHO
(b) CH₃CHO
(c) HCHO
(d) CH₃ – CH₂ – CHO
Answer:
(c) HCHO

Question 150.
Acetaldehyde does not answer
(a) lodoform test
(b) Lucas test
(c) Benedict test
(d) Tollen’s reagent test
Answer:
(b) Lucas test

II. Fill In the blanks.

The aldehyde Pyridoxal function as a ………….
p – acetylated amino phenol is used to reduce ………….
The TUPAC name of CH₃ – CH = CH – CHO is ………….
The TUPAC name of CH₂ = CH – CHO is ………….
The formula of mesityl oxide is ………….
The name of is ………….
But – 2 – ene gives 2 moleafethanal by ………….
…………. Olefines give formaldehyde as one of the product.
Hydration of …………. in the presence of 40% dilute sulphuric acid and 1% HgSO₄ gives Ethanal.
Calcium formate on …………. gives methanal and CaCO₃.
Dry distillation of …………. gives propanone and CaCO₃.
Tn Rosenmund’s reduction reaction …………. is the catalyst and …………. is the catalytic poison.
…………. selectively reduces alkyl cyanide to form imines which on hydrolysis gives aldehyde.
Side chain oxidation of toluene in the presence of KMnO₄ gives ………….
The oxidising agent used to convert toluene to benzaldehyde is ………….
Acetyl chloride reacts with …………. to form acetone.
Addition of …………. finds application in. the separation and purification of carbonyl compounds.
Aliphatic aldehyde except …………. react with an ethereal solution of ammonia to form aldimines.
Formaldehyde reacts with ammonia to form …………. which is used to treat urinary infection.
Nitration of Urotropine under controlled condition gives an explosive ………….
RDX is also called …………. or ………….
With ammonia, benzaldehyde form a complex condensation product called ………….
The oxidation of unsymmetrical ketone is governed by ………….
The reducing agent used in Clemmensen reduction is ………….
The reducing agent used in woif-kishner reduction is ………….
Symmetric diols are called ………….
Aldehydes which do not have …………. undergo disproportionation reaction (or) cannizaro reaction.
The reagent used in the conversion of Benzaldehyde to Benoin is ………….
In Knoevenagal reaction …………. act as the basic catalyst.
The formula of Benzal aniline (or) Schiffs base is ………….
Benzaldehyde condenses with N, N – dimethyl aniline in the presence of strong acids to form ………….
…………. is ammoniacal silver nitrate solution.
…………. is a mixture of CuSO₄ + Sodium citrate + NaOH.
40% aqueous solution of formaldehyde is known as …………..
Paraldehyde is used in medicine as ………….
Acetone is used in the manufacture of thermo softening plastic ………….
…………. is used in perfumery and as a hypnotic under the name hyphone.
…………. cannot be prepared by grignard reagent since the acid contains only one carbon atom.
Most of carboxylic acid exist as …………. in its vapour state.
…………. is 6 to 8% solution of acetic acid in water.
…………. is used to convert acetic acid to ethane at 473 K.
…………. reaction is generally used for the preparation of esters of higher alcohol from that of a lower alcohol.
Formic acid is used in medicine for treatment of ………….
The conversion of acetamide to methylamine by the action of caustic alkali and Bromine is known as ………….
…………. is used as food preservative.
…………. is used in the detection and estimation of – OH, – NH₂, groups in organic compounds.
…………. is used in the preparation of artificial fruit essences.
The conversion of Benzene to Benzaldehyde by the action of carbon monoxide and HCl is known as ………….
The product formed when formaldehyde condensed with acetone is ………….
Benzaldehyde condenses with acetaldehyde to form ………….

Answer:

Coenzyme
Fever
But – 2 – enal
Prop – 2 – enal
(CH₃), C = CHCOCH₃
3-Oxo pentanal
Ozonolysis
Terminal
Ethyne
Dry distillation
Calcium ethanoate
Pd, BaSO₄
Diisobutvl aluminum hydride
Benzoic acid
CrO₂Cl₂ Chromyl chloride
Dimethyl cadmium
NaHSO₃
Formaldehyde
Urotropinc (or) Hexamethylene tetramine
RDX (or) Research and development explosive
Cyclonite(or)cyclotrimethylene trinitramine
Hydrobenzamide
Popott’s rule
Zn + Hg / conc.HCl
NH₂ – NH₂ + C₂H₅ONa
Pinacol
a – hydrogen atom
Alcoholic KCN
Pyridine
C₆H₅CH = N – C₆H₅
Triphenyl methane dye or malachite green dye
Tollen’s reagent
Benedict’s solution
Formalin
Hypnotic
Perspex
Acetophenone
Formic acid HCOOH
Dimer
Vinegar
HI + Red P
Transesterification
Gout
Hoff mann’s degradation
Sodium benzoate
Acetyl chloride
Ethyl acetate
Gattermann – koch reaction
4 – hydroxy – butane – 2 – one
Cinnamaldehyde

III. Match the following.
Match the column I and II using the code given below the column.

Question 1.

Answer:
(a) 3 2 4 1

Question 2.

Answer:
(b) 3 1 4 2

Question 3.

Answer:
(c) 3 4 1 2

Question 4.

Answer:
(a) 2 3 4 1

Question 5.

Answer:
(d) 3 4 1 2

Question 6.

Answer:
(a) 2 3 1 4

Question 7.

Answer:
(a) 4 3 1 2

Question 8.

Answer:
(a) 3 4 1 2

Question 9.

Answer:
(a) 2 4 1 3

Question 10.

Answer:
(a) 3 1 4 2

Question 11.

Answer:
(a) 2 4 1 3

Question 12.

Answer:
(a) 2 3 4 1

IV. Assertion and reasons.

Question 1.
Assertion(A): In Rosenmund’s reduction, BaSO₄ act as catalyst pòison.
Reason (R): In Rosenmund’s reduction, BaSO₄ act as catalytic poison to pd catalyst so that aldehyde cannot be further reduced ti alcohol.
(a) Both A and R are correct and R is the correct explanation of A.
(b) Both A and R are correct but R is not correct explanation of A
(c) A is correct but R is wrong
(d) A is wrong but R is correct
Answer:
(a) Both A and R are correct and R is the correct explanation of A.

Question 2.
Assertion(A): Aldehydes and ketones have high high boiling point as compared to hydrocarbon and ether of comparable molecular mass.
Reason (R): It is due to weak molecular association in aldehydes and ketones arising out of the dipole – dipole interactions.
(a) Both A and R are correct and R is the correct explanation of A.
(b) Both A and R are wrong
(c) A is correct but R is wrong
(d) A is wrong but R is correct
Answer:
(a) Both A and R are correct and R is the correct explanation of A.

Question 3.
Assertion(A): The boiling point of aldehydes and ketones are much lower those of corresponding alcohols and carboxylic acids.
Reason (R): Alcohols and carboxylic acids possess intermolecular hydrogen bonding and so have high boiling point.
(a) Both A and R are correct but R is not the correct explanation of A.
(b) Both A and R are correct and R ¡s the correct explanation of A
(c) A is correct but R is wrong
(d) A is wrong but R is correct
Answer:
(b) Both A and R are correct and R ¡s the correct explanation of A

Question 4.
Assertion(A): Aldehydes and ketones have high dipole moment.
Reason (R): The carbonyl group of aldehydes and ketones contain a double bond between carbon and oxygen. Oxygen is more electronegative than carbon and it attracts the shared pair of electron which makes the carbonyl group as polar.
(a) Both A and R are correct and R is the correct explanation of A.
(b) Both A and R are correct but R is not the correct explanation of A
(c) A is correct but R is wrong
(d) A is wrong but R is correct
Answer:
(a) Both A and R are correct and R is the correct explanation of A.

Question 5.
Assertion(A): Addition of sodium bisuiphite finds application in the separation and purification of carbonyl compound.
Reason (R): The bisuiphite addition compound is water soluble and the solution is treated with mineral acid to regenerate the carbonyl compounds.
(a) Both A and R are correct and R is the correct explanation of A.
(b) Both A and R are correct but R is not the correct explanation of A
(c) Both A and R are wrong
(d) A is correct but R is wrong
Answer:
(a) Both A and R are correct and R is the correct explanation of A.

Question 6.
Assertion(A): Acetaldehyde does not undergo cannizaro reaction.
Reason (R): Cannizaro reaction is a characteristic of aldehyde having no α – H atom. Acetaldehyde contains 3 α – H atoms.
(a) Both A and R are correct and R is the correct explanation of A.
(b) Both A and R are correct but R. is not correct explanation of A
(c) A is correct but R is wrong
(d) A is wrong but R is correct
Answer:
(a) Both A and R are correct and R is the correct explanation of A.

Question 7.
Assertion(A): Acetaldehyde and acetone are readily undergo aldol condensation reaction in the presence of dilute base.
Reason (R): Aldehyde or ketone having α – hydrogen atom add together to give aldol or ketol.
(a) Both A and R are correct but R is not the correct explanation of A.
(b) Both A and R are correct and R is the correct explanation of A
(c) A is correct but R is wrong
(d) A is wrong but R is correct
Answer:
(b) Both A and R are correct and R is the correct explanation of A

Question 8.
Assertion(A): Carboxylic acids have higher boiling point than aldehyde and ketone of comparable molecular mass.
Reason (R): This is due to more association of carboxylic acid. Molecules through intermolecular hydrogen bonding.
(a) Both A and R are correct but R is not correct explanation of A.
(b) Both A and R are correct and R is the correct explanation of A
(c) A is correct but R is wrong
(d) A is wrong but R is correct
Answer:
(b) Both A and R are correct and R is the correct explanation of A

Question 9.
Assertion(A): Lower aliphatic carboxylic acids arc miscible with water but higher carboxylic acids are insoluble in water.
Reason (R): Lower carboxylic acids are able to form hydrogen bond with water whereas higher carboxylic acids have increased hydrophobic interaction of hydrocarbon part.
(a) Both A and R are correct and R is the correct explanation Of A.
(b) Both A and R are correct but R is not correct explanation of A
(c) A is correct but R is wrong
(d) A is wrong but R is correct
Answer:
(a) Both A and R are correct and R is the correct explanation Of A.

Question 10.
Assertion(A): Carboxylic acid do not give the characteristic reaction of carbonyl group as given by aldehyde and ketone.
Reason (R): The carbonyl carbon of carboxylic acid is involved in resonance.
(a) Both A and R are correct but R is not correct explanation of A.
(b) Both A and R are correct and R is the correct explanation of A
(c) Both A and R are correct and R is the correct explanation of A.
(d) Both A and R are correct but R is not correct explanation of A
Answer:
(c) Both A and R are correct and R is the correct explanation of A.

Question 11.
Assertion(A): Benzoic acid does not undergo friedel crafts reaction.
Reason (R): This is due to the strong deactivating nature of the carboxyl group
(a) Both A and R are correct and R is the correct explanation of A.
(b) Both A and R are correct but R is not the correct explanation of A
(c) A is correct but R is wrong
(d) A is wrong but R is correct
Answer:
(a) Both A and R are correct and R is the correct explanation of A.

Question 12.
Assertion(A): Formic acid can act as a strong reducing agent
Reason (R): Formic acid contains both aldehyde as well as an acid group.
(a) Both A and R are wrong
(b) A is correct but R is wrong
(c) A is wrong but R is correct
(d) Both A and R are correct and R is the correct explanation of A.
Answer:
(d) Both A and R are correct and R is the correct explanation of A.

Question 13.
Assertlon(A): Trichioro acetic acid is more acidic than acetic acid.
Reason (R): Cl^– is a electron withdrawing group and acidity increases with increasing number of electron withdrawing substituents on the α – carbon.
(a) Both A and R are correct and R is the correct reason of A.
(b) Both A and R are correct but R is not correct reason of A.
(c) A is correct but R is wrong
(d) A is wrong but R is correct.
Answer:
(a) Both A and R are correct and R is the correct reason of A.

V. Find the odd one out and give the reasons.

Question 1.
(a) Methanal
(b) Ethanal
(c) Phenyl metbanal
(d) Prop – 2 – enal
Answer:
(c) Phenyl metbanal
It is an aromatic aldehyde where as others are aliphatic aldehydes.

Question 2.
(a) Formic acid
(b) Acetic acid
(c) Benzoic acid
(d) Propanoic acid
Answer:
(d) Propanoic acid
It can act as reducing agent where as other acids are not act as reducing agents.

Question 3.
(a) HCHO
(b) C₆H₅CHO
(c) CCI₃CHO
(d) CH₃CHO
Answer:
(d) CH₃CHO
CH₃CHO. It contains α – H atom and undergoes aldol condensation where as others do not have α – H atoms and they undergo cannizaro reactions.

Samacheer Kalvi 12th Chemistry Carbonyl Compounds and Carboxylic Acids 2 Mark Questions and Answers

Question 1.
Write the name of the following compounds.
Answer:

Question 2.
What happens But – 2 – ene is ozonised followed by hydrolysis?
Answer:

Question 3.
Explain the action of ozone with 2 – methyl but – 2 – ene followed by hydrolysis with zinc?
Answer:

Question 4.
What happens when Ethyne is hydrolysed in the presence of HgSO₄ and H₂SO₄?
Answer:

Question 5.
How would you convert prop – 1 – yne to propanone?
Answer:
Prop – 1- lyne on hydrolysis with HgSO₄ and H₂SO₄ gives propanone as product.

Question 6.
Explain about the dry distillation of Calcium ethanoate.
Calcium ethanoate on dry distillation gives propanone as product.
Answer:

Question 7.
Explain Rosenmund reduction.
Answer:
Aldehydes can be prepared by the hydrogenation of acid chloride, in the presence of palladium supported by Barium sulphate. This reaction is called Rosenmund reduction.

In the above reaction, BaSO₄ act as a catalytic poison to palladium catalyst, so that aldehyde cannot be further reduced to alcohol.

Question 8.
Explain Stephen’s reaction.
Answer:
In Stephen’s reaction, alkyl cyanide are reduced using SnCl₂ / HCI, imines arc formed which on hydrolysis gives corresponding aldehyde.

Question 9.
Explain the action of Diisobutyl aluminium hydride (DIBAL – H) and H₂O with hex – 4 – en nitrile.
Answer:

Question 10.
Explain about Cattermann – koch reaction.
Answer:
Benzene reacts with carbon monoxide and HCl in the presence of AlCl₃ and CuCl to give Benzaldehyde. This reaction is known as Gattermann – Koch reaction.

Question 11.
How would you manufacture benzaldehyde from toluene?

This is the commercial method for the manufacture of Benzaldehyde.

Question 12.
Explain the action of dialkyl cadmium with acetyl chloride?
Answer:

Question 13.
Explain the nucleophilic addition of HCN with eth anal?
Answer:

Question 14.
Which reaction finds application in the separation and purification ofcarbonyl compound? Explain.

The bisuiphite compound is water soluble and the solution is treated with minerai acid to regenerate the carbonyl compound. So the above reaction is used in the separation and purification of carbonyl compound.

Question 15.
Complete the following reactions.
Answer:

Question 16.
What Is Clemmensen reduction ? Explain it.
Answer:
Aldehyde and ketones when heated with zinc amalgam and concentrated hydrochloric acid give hydrocarbons. This reaction is known as Clemmensen reduction.

Question 17.
Complete the following reactions.
Answer:

Question 18.
Explain Wolf Kishner reduction with suitable example.
Answer:
Wolf Kishner reduction:

Question 19.
How would you obtain chloroform from acetone?
Answer:
When acetone is treated with chlorine and alkali, chloroform is formed.

Question 20.
What happen when alcoholic KCN reacts with Benzaldehyde? (or) explain Benzoin condensation.
Answer:
Benzaldehyde reacts with alcoholic KCN to form Benzoin.

Question 21.
Explain about SchilT’s reagent test?
Answer:
Dilute solution of aldehyde when added to Schifl’s reagent (Rosaniline hydrochloride dissolved in water and its red colour decolourised by passing SO₂) yields its red colour. This is known as Schiffs’ test for aldehyde. Ketones do not give this test. Acetone however gives a positive test but slowly.

Question 22.
What are used of Urotropine? Give its structure.
Answer:
This is the structure of Urotropme (Hexamethylene tetramine)
1. Urotropine is used as a medicine to treat urinary infection.

2. Nitration ofUrotropine under controlled condition gives an explosive RDX (Research and development explosive). It is also called cyclonite or cyclotri methylene trinitramine.

Question 23.
Mention the uses of aromatic ketone.
Answer:

Acetophenone has been used in perfumery arid as a hypnotic under the name hyphone.
Benzophenone is used in perfumery and in the preparation of benzhydrol drop.

Question 24.
Write the structure and IUPAC name of the following compounds?

(i) Malonic acid

(ii) Succinic acid

(iii) Glutaric acid

(iv) Adipic acid

Answer:

Question 25.
Starting from methyl magnesium iodide, how would you prepare acetic acid?
Answer:

Question 26.
Convert phenyl magnesium bromide into Benzoic acid?
Answer:

Question 27.
Explain the hydrolysis reaction of the following with equation?

(CH₃CO)₂O
(C₆H₅CO)₂O

Answer:

Question 28.
Explain the action of alkaline potassium permanganate with toluene?
Answer:

Question 29.
Lower aliphatic carboxylic acids are miscible with water but higher carboxylic acids are insoluble in water. Give reason. (or) Acetic acid is soluble in water but hexanoic acid in insoluble in water. Why?
Answer:
Aliphatic acids are miscible with water due to the formation of hydrogen bonds with water. Higher carboxylic acids are insoluble in water due to increased hydrophobic interaction of hydrocarbon part. Thats why acetic acid is soluble in water whereas hexanoic acid is insoluble in water.

Question 30.
What is Vinegar? How will you get glacial acetic acid?
Answer:

Vinegar is 6 to 8% solution of acetic acid in water.
Pure acetic acid is called glacial acetic acid. Because it forms ice like crystal when cooled.

When aqueous acetic acid is cooled at 289.5 K, acetic acid solidifies and forms ice like crystals, where as water remains in liquid state and removed by filtration. This process is repeated to obtain glacial acetic acid.

Question 31.
Explain the action of the following reagents with acetic acid.

(i) PCI₅

(ii) SOCI₂

Answer:

Question 32.
Complete the following reactions.

Answer:

Question 33.
What happens when thionyl chloride reacts with benzoic acid?
Answer:
When Benzoic acid reacts with thionyl chloride, Benzoyl chloride is formed as product.

Question 34.
Explain Kolbe’s electrolytic decarboxylation.
Answer:
The aqueous solution of sodium or potassium salts of carboxylic acid on electrolysis gives alkanes at anode. This reaction is called kolbe’s electrolysis.

Question 35.
What happens when ammonia reacts with acetic acid?
Answer:

Question 36.
Explain the action of heat on acetic acid in the presence of phosphorous pentoxide.
Answer:

Question 37.
Explain the a – halogenation take place in acetic acid. (or) Explain IIell-Volhard-zelinsky reaction (HVZ reaction)?
Answer:

Carboxylic acids having an α – hydrogen are halogenated at the α – position on treatment with chlorine or bromine in the presence of small amount of red phosphorus to form a – halo carboxylic acids. This reaction is known as Hell – Volhard – Zelinsky reaction (HVZ reaction)

Question 38.
Acidity increases with increasing number of electron rithdrawing substituents on the α – carbon. Explain with example.
Answer:
Acidity increases with increasing number of electron withdrawing substituents on the α – carbon atom. For example,
Cl₃C – COOH > Cl₂CH – COOH > Cl – CH₂COOH > CH₃COOH
The effect of various, electron withdrawing groups on the acidity of a carboxylic acid follows the order,
– NO₂ > – CN > – F > – Cl > – Br > – I > Ph

Question 39.
Trichloro acetic acid is more acidic than acetic acid. Give reason.
Answer:
Cl^– is an electron withdrawing substituent. Acidity increases with the increasing number of electron withdrawing substituents on the α – carbon. So trichioro acetic acid is more acidic than acetic acid. CCI₃COOH is more acidic than CH₃COOH.

Question 40.
Fluoro acetic acid is more acidic than iodoacetic acid. Give reason.
Answer:
Acidity increases with increasing electro negativity of the substituents. F is more electro negative.
F – CH₂ – COOH > Cl – CH₂COOH > Br – CH₂ – COOH > 1 – CH₂ – COOH
So Fluoro acetic acid is more acidic than iodoacetic acid.

Question 41.
What are carboxylic acid derivatives? Give four examples.
Answer:
1. Carboxylic acid derivatives are compounds in which carboxylic acid – OH group is replaced by the atom or the group.

Question 42.
Which is the best method to prepare acetyl chloride from acetic acid? why?
Answer:
Acetyl chloride is prepared from acetic acid by the action of thionyl chloride. This method is superior to others as the by products being gases escape leaving the acid chloride in the pure state.

Question 43.
Acetyl chloride fumes when exposed to air. Give reason.
Answer:
Acetyl chloride emit pale fumes of hydrogen chloride when exposed to air on account of their reaction with water vapour.

Question 44.
What happens when acetyl chloride is treated with ethanol?
Answer:

This reaction is also known as alcoholysis.

Question 45.
Explain ammonolysis reaction of acid chloride (or) what happens when ammonia reacts with acetvl chloride?
Answer:

Question 46.
What happens when acetic anhydride reacts with ethyl alcohol?
Answer:

Question 47.
Explain the reaction of ammonia with acetic anhydride.
Answer:

Question 48.
Complete the following reaction.
Answer:

Question 49.
What is transesterification? Explain with example.
Answer:
Esters of an alcohol can react with atiother alcohol in the presence of a mineral acid to give the ester of second alcohol. The interchange of alcohol portions of the esters is termed transesterification.

Question 50.
Explain the action of ammonia with ethyl acetate.
Answer:

Question 51.
How is ethyl acetate react with PCL₅?
Answer:

Question 52.
What happens when methyl cyanide is partially hydrolysed by cold conc. HCl?
Answer:

Question 53.
Explain the action of P₂O₅ with acetamide with equation.
Answer:

Question 54.
Describe Hoffmann degradation reaction. (or) How would you obtain methyl amine from acetamide?
Answer:
Acetamide reacts with bromine in the presence of caustic alkali to form a primary amine carrying one carbon less than the parent amide.

Question 55.
How would you preparate ethyl amine from acetamide?
Answer:

Question 56.
What are the used of acetyl chloride?
Answer:

Acetyl chloride is used as acetylating agent in organic analysis
it is used in the detection and estimation of – OH, – NH₂ groups in organic compounds.

Question 57.
Arrange the following compounds ¡n increasing order of their reactivity in nucleophilic addition reactions.

Ethanal, Propanal, Propanone, Butanone
Benzaldehyde, p – Tolualdehyde, p – Nitrobenzaldehyde, Acetophenone

Answer:

Butanone < Propanone < Propanal <Ethanal
Acetophenone < p – Tolualdehyde < Benzaldehyde < p – Nitrobenzaldehyde

Question 58.
Give the IUPAC names of the following compounds:

(i) PhCH₂CH₂COOH

(ii) (CH₃)₂C = CHCOOH

Answer:

3 – Phenylpropanoic acid
3 methylbut – 2 – enoje acid
2 – methylcyclohexane carboxylic acid
2, 4, 6 – Trinitorbenzoic acid or 2, 4, 6, – Trinitrobenzene carboxylic acid

Question 59.
Although phenoxide ion has more number of resonating structures than carboxylate ion, carboxylic acid is a stronger acid than phenol? Why?
Answer:
In carboxylate ion -ve charge is delocalised over two oxygen atoms whereas in phenoxide ion the -ve charge is delocalised over one oxygen atom. Therefore carboxylate ion is more stable than phenoxide ion and that is why carboxylic acids are more acidic than phenols.

Question 60.
How is aminoethane obtained from ethanal (acetaldehyde)?
Answer:

Question 61.
Why HCOOH does not give Hell – Voihard Zelinsky reaction but CH₃COOH does?
Answer:
CH₃COOH contains α – hydrogen atom and hence gives HVZ reaction but HCOOH does not contain an α – hydrogen atom and hence does not give HVZ reaction.

Question 62.
Write IUPAC names of the following.

Answer:

3 – Methylpent – 2 – 3n 3 – 1, 5 – dioic acid
6 – Bromo -3 – hydroxy- 5 – nitrobenzoic acid

Question 63.
Give chemical tests to distinguish between the following pair of compounds.

Phenol and Benzoic acid
Benzaldehyde and Acetophenone

Answer:

By adding feme chloride, phenol will give violet colour whereas benzoic acid will not react.
Adding I₂ and NaOH, Acetophenone will give yellow ppt. of iodoform whereas benzaldehyde will not react.

Question 64.
Give chemical tests to distinguish between the following pair of compounds.

Propanoyl chloride and propanoic acid
Benzaldehyde and Acetophenone

Answer:
1. On adding NaHCO₃, solution to each of them, propanoyl chloride will not react whereas propanoic acid will give brisk èfferevescence due to the evolution of CO₂.

2. On adding I₂ and NaOH, Acetophenone will give yellow ppt, of iodoform whereas benzaldehyde will not react

Question 65.
Give chemical tests to distinguish between the following pair of compounds.

Propanal and propanone
Benzaldehyde and Benzoic acid

Answer:

On adding Tollen’s reagent, propanal will give silver mirror whereas propanone does not react.
On adding NaHCO₃ solution, benzaldehyde will not react whereas benzoic acid will give brisk effervescence due to the evolution of CO₂.

Question 66.
Out of acetophenone and benzophenone, which one will give iodoform test? Write the reaction involved. (The compound should have CH₃CO group to show the iodoform test).
Answer:
Acetophenone (C₆H₅COCH₃) contains the group (CH₃CO) attached to the carbon atom and hence give lodoform test while benzophenone does not contain this group and hence does not give iodoform test.

Question 67.
Why does methanal not give aidol condensation while ethanol forms an aldol?
Answer:
This is because only those compounds which haie α – hydrogen atoms can undergo aldol condensation reactions. Ethanol possesses α – hydrogen and therefore undergoes aldol condensation. Methanal does not have α – hydrogen atoms, hence does not undergo aldol condensation reactions.

Samacheer Kalvi 12th Chemistry Carbonyl Compounds and Carboxylic Acids 3 Mark Questions and Answers.

Question 1.
Draw the structure and IUPAC name of the following compounds.

(i) Acrolein

(ii) Crotonaldehyde

(iii) Glyceraldehyde

Answer:

Question 2.
Draw the structure and IUPAC name of the following compounds.

(i) Mesityl oxide

(ii) Acetophenone

(iii) Benzophenone

Answer:

Question 3.
Explain about the structure of carbonyl group.
Answer:
1. The carbonyl carbon

is sp² hybridised and carbon – oxygen bond is similar to carbon carbon double bond in alkenes. The carbonyl carbon forms three o bonds using their three sp² hybridised orbital. One of the sigma bond is formed with oxygen and the other two with hydrogen and carbon (in aldehydes) or with two carbons (in ketones). All the three ‘a’ bonded atoms arc lying on the same plane.

2. The fourth valence electron of carbon remains in its unhybridised ‘2p’ orbital which lies perpendicular to the plane and it overlaps with 2p orbital of oxygen to form a carbon – oxygen bond.

3. The oxygen atom has two non-bonding pairs of electrons, which occupy its remaining two P orbitais. Oxygen, the second most electro negative atom attracts the shaired pair of electron between the carbon and oxygen towards itself and hence the bond is polar. This polarisation contributes to the reactivity of aldehydes and ketones.

Question 4.
How are the following compounds are prepared by the dry distillation of calcium salt of carboxylic acids?

(i) Methanal

(ii) Ethanal

Answer:

Question 5.
How will you prepare benzaldehyde from methyl benzene? (or) Explain Etard reaction.
Answer:
When chromylchloridc is used as an oxidising agent, toluene gives benzaldehyde. This reaction is called Etard reaction. Acetic anhydride and CrO₃ can also be used for this reaction.

Question 6.
How would you prepare the following compounds by Friedel Crafts acylation?

(i) Acetophenone

(ii) Benzophenone

Answer:

Question 7.
Aldehydes and ketones have high boiling point as compared to hydrocarbons and ethers of comparable molecular mass and less than that of alcohols. Give reason.
Answer:
Aldehydes and ketones have high boiling point as compared to hydrocarbons and ethers of comparable molecular mass. It is due to the weak molecular association in aldehyde and ketone arising out of the dipole-dipole interactions.

These dipole – dipole interactions are weaker than intermolecular H – bonding. The boiling points of aldehydes and ketones are much lower than those of corresponding alcohols and carboxylic acids which possess inter molecular hydrogen bonding.

Question 8.
Explain the mechanism of nucleophilic addition reactions of aldehyde and ketone?
Answer:
1. Nucleophilic addition reaction is the most common reactions of aldehydes and ketones. The carbonyl carbon cames a small degree of positive charge.

2. Nucleophile such as CN^– can attack the carbonyl carbon and uses its bond pair to forni a new carbon – nucleophile’ a ‘bond, at the same time two electrons from the carbon – oxygen double bond move to the most electronegative oxygen atom.

3. This results in the formation of an alkoxide ion. In this process, the hybridisation of carbon changes from sp² to sp³

The tetrahedral intermediate can be protonated by water or an acid to form an alcohol.

Question 9.
How acetone reacts with the following reagents?

(i) NH₂OH

(ii) NH₂ – NH₂

(iii) C₆H₅NH – NH₂

Answer:

Question 10.
What is Urotropine? How is It prepared? Mention Its structure and uses.
Answer:
1. Urotropine is hexamethylene tetramine. N

2. Formaldehyde reacts with ammonia to form hexamethylene tetramine, which is called Urotropine. HC CH1 CH

3. Urotropine is used as a medicine to treat urinary infection.

4. Nitration of Urotropine under controlled condition gives an explosive RDX (Research and development explosive). It is also called cyclonite or cyclotri methylene trinitramine.

Question 11.
What is popoff ‘s rule? Explain with an example.
Answer:
The oxidation of unsymmetrical ketones is governed by Popoff’s rule. It states that during the oxidation of an unsymmetrical ketone, a (C – CO) bond is cleaved in such a way that the keto group stays with the smaller alkyl group. Example:

Question 12.
Explain the action of magnesium amalgam and water with acetone?
Answer:

Question 13.
Describe crossed aldol condensation with two examples.
Answer:
Aldol condensation can takes place between two different aldehyde or ketones or between one aldehyde and one ketone is called crossed or mixed aldol condensation. E.g.,

Question 14.
Explain Claisen – Schmidt condensation.
Answer:
Benzaldehye condenses with acetaldehyde or acetone in the presence of dil. alkali at room temperature to form unsaturated aldehyde (or) ketone. This type of reaction is called Claisen – Schmidt condensation.

Question 15.
What is crossed cannizaro reaction? Explain It.
Answer:
When Cannizaro reaction (Auto redox reaction) takes place between two different aldehyde, the reaction is called as crossed cannizaro reaction.

In crossed cannizaro reaction more reactive aldehyde is oxidized and less reactive aldehyde is reduced.

Question 16.
How will you prepare malachite green dye from Benzaldehyde?
Answer:
Benzaldehyde condenses with tertiary aromatic amines like N, N – dimethyl aniline in the presence of strong acids to triphenyl methane dye.

Question 17.
How Is chlorine react with Benzaldehyde?

In the presence of catalyst
In the absence of catalyst

Answer:

Question 18.
Explain about 3 test for aldehyde
Answer:
1. Tollen’s reagent test:
When an aldehyde is warmed with Tollens reagent(Ammonical silver nitrate), a bright silver mirror is produced due to the formation of silver metal. This reaction is also called silver mirror test for aldehydes.

2. Fehlings solution Test:
Fehlings solution is prepared by mixing equal volumes of Fehlings solution ‘A’ containing aqueous copper sulphate and Fehlings solution ‘B’ containing alkaline solution of sodium potassium tartarate (RocheLle salt) When aldehyde is warmed with Fehlings solution deep blue colour solution is changed to red precipitate of cuprous oxide.

3. Benedict’s solution Test:
Benedict’s solution is a mixture of CuSO₄ + sodium citrate + NaOH. Cu²⁺ is reduced by aldehyde to give red precipitate of cuprous oxide.

Question 19.
Mention the uses of formaldehyde.
Answer:

40% aqueous solution of formaldehyde is called formalin. It is used for preserving biological specimens.
Formalin has hardening effect, hence it is used for tanning.
Formalin is used in the production of thermo setting plastic known as bakelite, which is obtained by heating phenol with formalin.

Question 20.
What are the uses of acetaldehyde?
Answer:

Acetaldehyde is used for silvering of mirrors
Paraldehyde is used in medicine as a hypnotic.
Acetaldehyde is used in the commercial preparation of organic compounds like acetic acid, ethyl acetate etc.,

Question 21.
Write about the uses of Acetone.
Answer:

Acetone is used as a solvent, in the manufacture of smokeless powder (cordite)
It is used as a nail polish remover.
It is used in the preparation of suiphonal, a hypnotic.
It is used in the manufacture of thermosoftening plastic Perspex.

Question 22.
What are the uses of Benzaldehyde?
Answer:

as a flavoring agent
in perfumes
in dye intermediates
as starting material for the synthesis of several other organic compounds like cinnamaldehyde, cinnamic acid, benzoyl chloride etc.

Question 23.
Carboxylic acids have higher boiling pint than aldehyde, keton and even alcohols of comparable molecular masses. Give reason.
Answer:
Carboxylic acids have higher boiling point due to more association of acid molecules through inter molecular hydrogen bonding.

In fact, most of the carboxylic acids exist as dimer in its vapour phase.

Question 24.
What happens when ethanoic acid reacts with the following reagents?

LiAIH₄
Red P, Hl

Answer:
1. When ethanoic acid reacts by LiAIH₄, partial reduction take place and ethanol is formed as a product.

2. When ethanoic acid is treated with HI and red phosphorous, complete reduction take place and alkane is formed as a product.

Question 25.
Explain the action of sodalime with sodium acetate. Name the type of reaction involved in ¡t.
Answer:
When sodium acetate is treated with sodalime, methane is formed.

Removal of CO₂ from carboxyl group take place in it and this is called decarboxylation

Question 26.
Explain about electrophilic substitution in Benzoic acid with example.
Answer:
Benzoic acid undergoes electrophilic substitution. The carboxyl group is a deactivating and meta directing group.
1. Halogenation.

2. Nitration

3. Sulphonation

Quesiton 27.
Formic acid act as reducing agent. Prove this statement.
Answer:
1. Formic acid contains both an aldehyde as well as an acid group. Hence, like other aldehydes, formic acid can easily be oxidised and therefore acts as a strong reducing agent.

2. Formic acid reduces Tollen’s reagent (ammonical silver nitrate solution) to metallic silver.

3. Formic acid reduces Fehling’s solution. It reduces blue coloured cupric ions to red coloured cuprous ions.

Question 28.
Give three test for carboxylic acid.
Answer:

In aqueous solution, carboxylic acid turn blue litmus red.
Carboxylic acids give brisk effervescence with. sodium bicarbonate due to the evolution of carbon – di – oxide.
When carboxylic acid is warmed with alcohol and conc H₂SO₄ it forms an ester, which is detected by its fruity odour.

Question 29.
Write a note about acidity of carboxylic acids.
Answer:
1. Carboxylic acids undergo ionisation to produce W and carboxylate ions in aqueous solution. The carboxylate ion is stabilised by resonance which make the Carboxylic acid to donate the proton easily.

2. The resonance structure of carboxylate ion are given below.

3. The strength of carboxylic acid can be expressed in terms of the dissociation constant(K_a):

The stronger the acid, the large will be its K_a value.
PK_a = – log K_a
A strong acid will have higher k_a value but smaller pK^a value, the reverse is true for weak acid.

Question 30.
Formic acid is more stronger than acetic acid. Justify this statement. The electron releasing groups (+I groups) increase the relative charge on the carboxylate ion and destabilise it and hence the loss of proton becomes difficult.
+ I groups are CH₃, – C₂H₅, – C₃H₇

Question 31.
Explain the order of relative reactivity of acid derivatives.
Answer:
1. The reactivity of the acid derivatives follows the order

2. The above order of reactivity can be explained in terms of
Basicity of the leaving group
(b) Resonance effect

3. Weaker bases are good leaving groups. Hence acyl derivatives with weaker bases as leaving groups (L) can easily rupture the bond and are more reactive. The correct order of the basicity of the leaving group is

Hence the reverse is the order of reactivity.

4. Lesser the electronegativity of the group, greater would be the resonance stabilization as shown below.

This effect makes the molecule more stable and reduces the reactivity of the acyl compound. The order of electronegativity of the leaving groups follows the order – Cl > – OCOR > – OR > – NH₂. Hence the order of reactivity of the acid derivatives with nucleophilic reagent follows the order
Acid halide > Acid anhydride> esters> Acid amides

Question 32.
Explain the following reaction with acetyl chloride

ammonolysis.

Answer:
Reaction with ammonia is known as arninonolysis

Question 33.
Explain the action of the following reagents with acetyl chloride?

Pd / BaSO₄
LiAIH₄

Answer:

Question 34.
Describe about Claisen condensation.
Answer:
Esters containing at least one α – hydrogen atom undergo self condensation in the presence of a strong base such as sodium ethoxide to form β – keto ester. This reaction is known as Claisen condensation.

Question 35.
Acid amides are generally amphoteric in nature. Justify this statement.
Answer:
1. Amides behave both as weak acid as well as weak base and thus show amphoteric character. This can be proved by the following reactions.

2. Acetamide (as base) reacts with hydrochloric acid to form salt

3. Acetamide (as acid) reacts with sodium to form sodium salt and hydrogen gas is liberated

Question 36.
Mention the uses of formic acid?
Answer:
Formic acid. It is used

for the dehydration of hides.
as a coagulating agent for rubber latex
in medicine for treatment of gout
as an antiseptic in the preservation of fruit juice

Question 37.
What are the uses of acetic acid?
Answer:
Acetic acid is used

as table vinegar
for coagulating rubber latex
for manufacture of cellulose acetate and poiy vinylacetate

Question 38.
Indicate the uses of Benzoic acid.
Answer:
Benzoic acid is used

as food preservative either in the pure form or in the form of sodium benzoate
in medicine as an urinary antiseptic
for manufacture of dyes

Question 39.
What are the uses of acetic anhydride?
Answer:
Acetic anhydride is used

acetylating agent
in the preparation of medicine like aspnn and phenacetin
for the manufacture plastics like cellulose acetate and poly vinyl acetate.

Question 40.
Mention the uses of Ethyl acetate?
Answer:
Ethyl acetate is used

in the preparation of artificial fruit essences.
as a solvent for lacquers.
in the preparation of organic synthetic reagent like ethyl acetoacetate.

Question 41.
Give reasons for the following.

Carboxylic acids do not give characteristic reactions of carboxyl group
Treatment of benzaldehyde with HCN gives a mixture of two isomers which cannot be separated even by careful fractional distillation.
Sodium bisuiphite is used for the purification of aldehydes and ketones.

Answer:
1. It is due to reasonance

2. It is because we get two optical isomers which have same physical properties, therefore, cannot be separated by fractional distillation.

3. Aldehydes and ketones form addition compounds with NaHSO₃ whereas any impurities do not. On hydrolysis, we get pure aldehydes and ketones back again.

Question 42.

(i) Describe the preparation of acetic acid from acetylene.

(ii) How can the following be obtained from acetic acid:

(a) Acetone

(b) Acetaldehyde

(iii) In what way can acetic acid be distinguished from acetone?

(iv) Why carboxylic acid do not give the characteristic reactions of a carbonyl group?

Answer:

(iii). Add I₂ and NaOH. Acetone will give yellow precipitate of iodoform whereas acetic acid does not react to give any yellow precipitate.(or) Add sodium bicarbonate solution Acetone will not react, but acetic acid will give brisk effervescence due to the evolution of CO₂.

(iv). Carboxylic acid does not give the characteristic reactions of carbonyl group due to reasonance effect by the virtue of which it does not have free

carbonyl group.

Question 43.
Account for the following

Cl – CH₂COOH is a stronger acid than CH₃COOH
Carboxylic acids do not give reactions of carbonyl group.

Answer:
1. MonochLoroacetic acid is comparatively stronger acid than acetic acid. This is due to – Cl as a – I group

2. Carboxylic acids do not give reactions of carbonyl group because the lone pair of electrons on the oxygen attached to hydrogen in the – COOH group are involved in resonance, which makes the carbon less electrophilic.

Question 44.
A group of students were given to study the properties of aldehydes and ketones in the lab. They recorded a few observation of their physical properties.

Why are aldehydes more reactive and moreioiuble than ketones?
What values of students are seen from the above act?

Answer:

Aldehydes are more soluble in water because they form hydrogen bond with water molecule.
Critical thinking

Question 45.
How will you distinguish between methanol and ethanol?
Answer:
By Iodoform test:
Ethanol having α – methyl group will give yellow ppt of iodoform whereas methanol, which do not have α – methyl group, will not give ppt. of iodoform.

Question 46.
There are two – NH₂ group in semicarbazide. However, only one is involved in the formation of semicarbazone. Why?
Answer:
Although semicarbazide has two – NH₂ groups but only one of them is involved in resonance as shown below.

As a result, e density on one of the – NH₂ group is reduced and hence it does not act as nucleophile. One pair of the other – NH₂ group is not involved in resonance and hence it is available for nucleophilic attack.

Question 47.
Explain why o – hydroxybenzaldehyde is a liquid at room temperature while p – hydroxybenzaldehyde is a high melting solid?
Answer:
Due to intramolecular H – bonding orthohydroxy benzaldehyde exists as discrete molecule whereas due to intermolecular H – bonding, p – hydroxybenzaldehyde exists as associated molecules. To break these intermolecular H – bonds, a large amount of energy is needed.

Consequently, p – hydroxybenzaldehyde has a much higher m.pt. and b.pt. than that of o – hydroxy benzaldehyde. As a result, o -hydroxy benzaldehyde is a liquid at room temperature while p – hydroxy benzaldehyde is a high melting solid.

Question 48.
A compound ‘X’ (C₂H₄O) on oxidation gives ‘Y’ (C₂H₄O₂), ‘X’ undergoes haloform reaction. On treatment with HCN ‘X’ form a product ‘Z’ which on hydrolysis gives 2 – hydroxy propanoic acid.

Write down the structures of ‘X’ and ‘Y’
Name the product when ‘X’ reacts with dii NaOH.
Write down the equations for the reaction involved.

Answer:

Structure of Y (CH₃COOH)

Question 49.

1. How will you prepare

Acetic anhydride and
Acetyl chloride from acetic acid?

Write the reactions involved in each case.
2. Why is the boiling point of an acid anhydride higher than the acid from which it is derived?
Answer:
1.

2. Acid anhydrides are bigger sized molecules than the corresponding acids, therefore have more surface area, more van der Waals’ forces of attraction and hence higher boiling points.

Question 50.
Suggest a reason for the large difference in the boiling point of butanol and butanal, although they have the same solubility in water.
Answer:
The b.pt. of butanol is higher than that of butanal because butanol has strong intermolecular H – bonding while butanal has weak dipole – dipole interactions. However both of them will form H – bond with water and hence are soluble.

Samacheer Kalvi 12th Chemistry Carbonyl Compounds and Carboxylic Acids 5 Mark Questions and Answers

Answer the following questions.

Question 1.
Explain the action of ammonia with the following compounds.

Answer:
(i). Formaldehyde reacts with ammonia to form hexa methylene tetramine, which is also known as UrotroDine.

Question 2.
Explain the mechanism of aldol condensation.
Answer:
In presence of dilute base NaOH, or KOH, two molecules of an aldehyde or ketone having α – hydrogen add together to give 3 – hydroxyl aldehyde (aldol) or – hydroxyl ketone (ketol). The reaction is called aldol condensation reaction.

Mechanism
The mechanism of aldol condensation of acetaldehyde takes place in three steps.
Step 1:
The carbanion is formed as the α – hydrogen atom is removed as a proton by the base.

Step 2:
The carbanion attacks the carbonyl carbon of another unionized aldehyde to form an alkoxide ion.

Step 3:
The alkoxide ion formed is protonated by water to form aldol.

The aldol rapidly undergoes dehydration on heating with acid to form a, f3 unsaturated aldehyde.

Question 3.
Explain the mechanism of Cannizaro reaction.
Answer:
1. In the presence of concentrated aqueous or alcoholic alkali, aldehydes which do not have α – hydrogen atom undergo self oxidation and reduction to give a mixture of alcohol and a salt of carboxylic acid. This reaction is called Cannizaro reaction.

2. Benzaldehyde on treatment with concentrated NaOH (50%) gives benzyl alcohol and sodium benzoate.

Mechanism
Cannizaro reaction involves three steps.
3. Step 1:
Attack of OH^– on the carbonyl carbons.

4. Step 2:
Hydride ion transfer

5. Step 3:
Acid – base reaction

Question 4.
Explain

Perkin’s reaction
Knocvenagal reaction.

Answer:
1. Perkin’s reaction
When an aromatic aldehyde is heated with an aliphatic acid anhydride in the presence of the sodium salt of the acid corresponding to the anhydride, condensation takes place and an α, β unsaturated acid is obtained. This reaction is known as Perkin’s reaction.

2. Knoevenagal reaction

Question 5.
Explain about electrophilic substitution reactions of Benzaldehyde and acetophenone.
Answer:

Question 6.
How would you prepare acetic acid from the following compounds.

Ethyl alcohol
Methyl cyanide
Ethyl acetate

Answer:

Question 7.
What is esterification? Explain the mechanism of esterification.
Answer:
When carboxylic acids are heated with alcohols in the presence of conc. HCI (or) dry HCI gas, esters are formed. This reaction is reversible and is called esterification.

Question 8.
An organic compound (A) (molecular formula C₈H₁₆O₂) was hydrolysed with dilute sulphuric acid to give a carboxylic acid (B) and an alcohol (C). Oxidation of (C) with chromic acid produced (B). (C) on dehydration gives but -1-ene. Write equations for the reactions involved.
Answer:
The relevant equations for all the reactions involved may be explained as follows.

Question 9.
An organic compound (A) of molecular formula CH₆ reacts with Br₂ in the presence of FeCI₃ gives (B) of formula C₆HBr. B on treatment with mg in the presence of dry ether gives (C) compound (C) on treatment with dry ice followed by hydrolysis gives a compound (D) of molecular formula C₇H₆O₂. Identify A,B,C,D and explain the reactions involved.
Answer:

Question 10.
A simplest aromatic hydrocarbon (A) reacts with methyl chloride in the presence of AICI₃ gives (B) C₇H₈. Compound (B) reacts with Br₂ along with light gives (C) of molecular formula C₇H₇Br (C) reacts with alcohol KCN gives (D) (C₈H₇N) (D) on acid hydrolysis gives (E) of formula C₈H₈O₂. Identify A,B,C,D,E and explain the reactions involved.
Answer:

Question 11.
An organic compound (A) is a calcium salt of acetic acid. (A) on dry distillation gives (B) of formula C₃H₆O. (B) on reaction with LiAIH₄ gives (C) of formula C₃H₈O (C) on heating with conc. H₂SO₄ gives (D) of molecular formula C₃H₆. Identify A,B,C,D and explain the reaction involved.
Answer:

Question 12.
An organic compound (A) of molecular formula C₇H₈O on oxidation with alkaline KMnO₄ gives (B) of formula C₇H₆O. (B) on reaction with CI₂ in the presence of catalyst FeCl₃ gives (C) of formula C₇HOCl. (B) on reaction with CI₂ in the absence of catalyst gives C₇H₅OCI. Identify A,B, C,D and explain the reaction involved.
Answer:

Question 13.
An organic compound (A) of molecular formula C₇H₆O reacts with acedaldehyde In the presence of sodium ethoxide gives (B) of formula C₉H₈O an unsaturated aldehyde. Compound (A) reacts with acetic anhydride in the presence of sodium acetate gives (C) and (D) of formula C₉HO₂ & C₂H₄O₂ respectively. Identify AB,C,D and explain the reaction involved.
Answer:
1. From the molecular formula (A) is identified as Benzaldehyde C₆H₅CHO.Benzaldehyde reacts with acetaldehyde to give cinnamaldehyde as B in Claisen condensation reaction.

2. Benzaldehyde reacts with acetic anhydride (Oerkin’s reaction) to give cinnamic acid (C) as product.

Question 14.
An aromatic aldehyde (A) of molecular C₇H₆O reacts with acidified KMnO₄ to give (B) of molecular formula C₇H₆O₂ calcium salt of compound (B) on dry distillation gives (C) of molecular formula C₁₃H₁₀O Compound (C) on Clemmenson’s reduction, gives (D) of formula C₁₃H₁₂O. Identify A,B,C,D and explain the reaction involved.
Answer:
1. From the molecular formula (A) is identified as Benzaldehyde C₆H₅CHO.Benzaldehyde on reaction with acidified KMnO₄ undergoes oxidation to give Bcnzoic acid as compound (B)

2. Calcium salt of Benzoic acid on dry distillaiton gives Benzophenone as compound (C)

3. Benzophenone undergoes Clemmenson reduction in the presence Zn amalgam and HCI gives Diphenyl methane as (D)

Question 15.
A simplest aromatic hydrocarbon (A) of formula C₆H₆ reacts with Bromine to gives (B) of molecular formula C₆H₅Br. (B) on treatment with magnesium metal in the presence of dry ether gives (C) . (C) on reaction with formaldehyde followed by acid hydrolysis gives (D) of formula C₇H₈O. Identify AB,C,D and explain the reaction involved.
Answer:
1. From the molecular formula (A) is identified as Benzene C6H6, Benzene reacts with Bromine to give bromobenzene as (B)

2. Bromobenzene reacts with Mg in the presence of dry ether gives phenyÍ magnesium bromide (Grignard reagent) as compound (C)

3. Phenyl magnesium bromide react with formaldehyde followed by acid hydrolysis gives Benzyl alcohol as product (D)

Question 16.
An organic compound (A) of molecular formula C₂H₃N on acid hydrolysis gives (B) of molecular formula C₂H₄O₂ calcium salt of (B) gives (C) of molecular formula C₃H₆O. Compound (C) on reduction of hydrazine and sodium ethoxide gives (D) of molecular formula C₃H₈. Identify A,B,C,D and explain the reaction involved.
Answer:
1.
2.
3. Wolf – Kishner reduction

Question 17.
An organic compound (A) of molecular formula C₇H₈ on reaction with hot alkaline KMnO₄ gives (B) of formula C₇H₆O₂ which gives brisk effervescence with NaHCO₃ solution. (B) on reaction with sodium hydroxide gives (C) of formula C₇H₅O₂Na. Compound (C) on treatment with sodalime gives (D) the simplest aromatic hydrocarbon.
Answer:
1. From the molecular formula (A) is identified as Toluene. Toluene on treatment with hot alkaline KMnO₄, oxidation take place and the product (B) formed is Benzoic acid.

2. Benzoic acid reacts with sodium hydroxide to give sodium benzoate as compound (C)

3. Sodium benzoate on reaction with sodalime (NaOH + CaO) decarboxylation take place and the product (D) formed is Benzene.

Question 18.
An organic compound (A) molecular formula C₃H₆O is resistant to oxidation but form a compound (B) (C₃H₈O) on reduction (B) reacts with HBr to form a bromide (C) which on treatment with alcoholic KOH forms an alkene (D) (C₃H₆). Deduce the structures of A,B,C and D.
Answer:

Question 19.
An organic compound (A) of molecular formula C₆H₆O gives violet colour with neutral FeCI₃. (A) on reaction with zinc dust gives (B) of formula C₆H₆ (B) on treatment with acetvl chloride in the presence of anhydrous AICI₃ gives (C) of formula C₈HO. (C) on Clemmenson reduction gives (D) of formula C₈H₁₀O. Identify A,B,C,D and explain the reaction involved.
Answer:

Question 20.
An organic compound (A) of molecular formula C₃H₆O reduces Tollen’s reagent on reaction with methyl magnesium bromide followed by acid hydrolysis gives (B) of formula C₄H₁₀O. (B) gives blue colour in victor meyer test. (B) on reaction with Cu at 573 K gives (C) of formula C₄H₈O (C) on reaction with hydrazine and sodium ethoxide gives (D) of molecular formula C₄H₁₀. identify A,B,C,D and explain the reactions involved.
Answer:
1. An organic compound (A) reduces Tollen’s reagent it must be an aldehyde. From the formula, it is identified as CH₃ – CH₂ – CHO propanal.

2. Propanal on reaction with methyl magnesium bromide followed by acid hydrolysis gives (B) as Butan – 2 – ol. It must be a secondary alcohol and gives blue colour with victor meyer’s test. H

4. Wolf – Kishner reduction.

Question 21.
An organic compound (A) of molecular formula C₇H₆O₂ reacts with PCI₅ to give (B) of formula C₇H₅OCl (B) on treatment with ammonia gives (C) of formula C₇H₇NO (C) on treatment with phosphorous pentoxide gives (D) of formula C₇H₅N. Identify A,BC,D and explain the reactions involved.
Answer:

Question 22.
An organic compound (A) of molecular formula C₃H₆ on hydration in the presence of H₂SO₄ gives (B) C₃H₅O which gives blue colour In victor meyer’s test. (B) on treatment with Cu at 573 K gives C₃H₆O a compound (C) on self condensation in the presence of magnesium amalgam and water gives (D) of formula C₆H₁₄O₂. Identify A,B,C,D and explain the reaction involved.
Answer:

Question 23.
An organic compound (A) of molecular formula C₂H₄O reduces tollen’s reagent to silver mirror. (A) on treatment with C₂H₅MgBr followed by acid hydrolysis gives (B) of formula C₄H₁₀O. (B) on reaction with Cu at 573 K gives (C) of formula C₄H₈O which does not reduce tollen’s reagent but answers iodoform test. Identify A,B,C,D and explain the reaction involved.
Answer:

Question 24.
An unknown aldehyde ‘A’ on reacting with alkali gives a b – hydroxy – aldehyde, which loses water to form an unsaturated aldehyde, 2 – butenal. Another aldehyde ‘B’ undergoes disporportionation reaction in the presence of conc. alkali to form products C and D. C is – an aryl alcohol with formula C₇H₈O.

Identify A and B.
Write the sequence of reactions involved
Name the product, when ‘B’ reacts with Zn amalgam and hydrochloric acid.

Answer:

1. ‘A’ is acetaldehyde ‘B’ is Benzaldehyde

2. reactuib are shown above.

Question 25.
An organic compound (A) of molecular formula C₄H₈ is symmetric alkene. (A) on ozonolysis gives 2 moles (B) of molecular formula C₂H₄O. (B) on reaction with ammonia gives (C) of molecular formula C₂H₅N.
Answer:
1. (A) is a symmetric alkene. From the molecular formula, it is identified as But – 2 – ene

2. But – 2 – ene on ozonolysis gives 2 moles of acetaldehyde as product (B)

Question 26.
An organic compound (A) of molecular formula C₂H₄O₂ gives brisk effervescence with sodium carbonate. (A) on reaction with thiony chloride gives (B) of formula C₂H₃OCI. (B) on reaction with Pd/BaSO₄ gives (C) of molecular formula C₂H₄O that reduces Tollen’s reagent to silver mirror. (C) on reaction with dilute NaOH gives (D) of molecular formula C₄H₈O₂. identify A,B,C,D and explain the reactions involved.
Answer:
1. (A) gives brisk effervescence with Na₂CO₃ means it must be a carboxylic acid. So (A) must be CH₃COOH Acetic acid.

2. Acetic acid reacts with thionyl chloride to give acetyl chloride CH₃COCI as (B)

3. Acetyl chloride reacts with Pd/BaSO₄, it undergoes Rosenmund’s reduction to give acetaldehyde as (C)

4. When acetaldehyde is warmed with dilute NaOH, it undergoes aldol condensation to

Question 27.
An organic compound (A) of molecular formula C₇H₈ reacts with CI₂ in the presence of ho light gives (B) of formula C₇H₆C₁₂. (B) on hydrolysis at 373 k gives (C) of formula C₇H₆O. (C) on treatment with 50% NaOH gives (D) and (E). Identify A,B,CD,E and explain the reactions involved.
Answer:
1. From the molecular formula (A) is identified as Toluene. ToÍuene reacts with Cl₂ in the presence of light gives Benzal chloride as (B)

2. Benzal chloride on hydrolysis at 373 k gives Benzaldehyde as (C)

3. Benzaldehyde when warmed with dilute NaOH undergoes cannizaro reaction to give Benzyl alcohol (D) and sodium benzoate (E)

Question 28.
An organic compound (A) of molecular formula C₂H₃OCI on reaction with pd and BaSO₄ gives (B) of formula C₂H₄O. (B) on reaction with LiAIH₄ gives (C) of formula C₂H₆O. (B) on reaction with 12 and NaOH gives (D) of formula CH₂ONa and iodoform. identify A,B,CD and explain the reactions involved.
Answer:
1. From the molecular formula (A) is identified as CH₃COCl (Acetyl chloride)

2. Acetyl chloride on treatment with Pd and BaSO₄ gives acetaldehyde CH₃CHO as (B)

3. Acetaldehyde on reaction with LiAIH₄ gives ethyl alcohol as (C)

4. Acetaldehyde when treated with I₂ and NaOH gives sodium formate (D) and iodoform CHI₃ as products.

Question 29.
An organic compound (A) of molecular formula C₇H₆O gives brisk effervescence with Na₂CO₃. Sodium salt of (A) on treatment with sodalime gives (B) a simplest aromatic hydrocarbon. (B) on reaction with acetyichioride in the presence of anhydrous AICI₃ gives (C) of formula C₈H₈O. (C) on treatment with conc. nitric acid and conc. sulphuric acid gives (D) of formula C₈H₇NO₃. Identify A,BC,D,E and explain the reactions involved.
Answer:
1. (A) gives brisk effervescence with Na₂CO₃ solution and it must be a carboxylic acid. (A) gives brisk effervescence with NNa₂CO₃ solution and it must be a carboxylic acid. (A) is C₆H₅COOH benzoic acid.

2. Sodium salt of benzoic acid on reaction with sodalime (decarboxylation) produces benzene as (B)

3. Benzene on treatment with acetyl chloride in the presence of anhydrous AlCl₃ gives acetophenone as (C)

4. Acetophenonc on reaction with conc. HNO₃ and cone. H₂SO₄ gives m – nitro acetophenone as (D)

Question 30.
An organic compound (A) of molecular formula C₂H₆O on reaction with acidified K₂Cr₂O₇ gives (B) of molecular formula C₂H₄O which on further oxidation gives (C) of molecular formula C₂H₄O₂. Compound (C) reacts with (A) in the presence of conc. H₂SO₄ gives (D) of molecular formula C₄H₈O₂. Identify A,B,C,D and explain the reaction Involved.
Answer:
1. An organic compound (A) of molecular formula C₂H₆O is identified as ethanol.

2. Ethanol on oxidation with acidified K₂Cr₂O₇ gives first acetaldehyde as (B) which on further oxidation gives acetic acid as (C)

3. Ethanol reacts with acetic acid in the presence of conc. H₂SO₄, esterification take place to give ethyl acetate as product (D)

Question 31.
An organic compound (A) of molecular formula C₂H₄O₂ gives brisk effervescence with Na₂CO₃. Acetyl chloride reacts with sodium acetate to give C₄H₆O₃ as (B). (B) on reaction with PCI₅ gives (C) of formula C₂H₁₀CI. (C) on reaction with ammonia gives (D) of molecular formula C₂H₅NO. Identify A,B,C,D and explain the reactions involved.
Answer:
1. Compound (A) gives brisk effervescence with Na₂CO₃ and so it must be a carboxylic acid. CH₃COOH (acetic acid) is compound A.

2. Acetyl chloride on heating with sodium acetate to give acetic anhydride as (B)

3. Acetic anhydride reacts with PCI₅ to give acetyl chloride CH₃COCI as (C)

4. Acetyl chloride on treatment with ammonia gives acetamide as (D)

Question 32.
An organic compound (A) of molecular formula C₂H₄O₂ reacts with PCI₅ to give (B) of formula C₂H₃OCI. (B) on treatment with ammonia gives (C) of formula C₂H₅NO. (C) on reaction with Br₂ and KOH gives CH₅N as (D). Identify A,B,C,D and explain the reactions involved.
Answer:
1. The organic compound (A) is identified as CH₃COOH (Acetic acid).

2. Acetic acid reacts with PCI₅ to form acetyl chloride as (B)

3. Acetyl chloride on reaction with ammonia gives acetamide as (C)

4. Acetamide on treatment with Br₂, and KOH gives methylamine as (D)

Question 33.
An organic compound (A) of molecular formula C₂H₅NO on treatment with LiAIH₄ gives (B) of formula C₂H₇N. (A) on treatment with Br₂ and excess of caustic alkali gives (C) of formula CH₅N. (A) on treatment with phosphorous pentoxide gives (D) of molecular formula C₂H₃N Identify A,B,C,D and explain the reaclions involved.
Answer:
1. The organic compound (A) is identified as CH₃CONH₂ acetamide.

2. Acetamide on treatment with LiAlH₄ gives ethylamine as product (B)

3. Acetamide on reaction with Br₂ and caustic alkali gives methyl amine as (C)

4. Acetamide on treatment with P₂O₅ gives Aceto nitrile (or) methyl cyanide as (D)

Question 34.
An organic compound (A) of molecular formula C₂H₅NO on reaction with P₂O₅ gives C₂H₃N(B). (B) on hydrolysis gives (C) of formula C₂H₄O₂ (C) on reaction with LiMB₄ gives (D) formula C₂H₆O. Identify A,B,C,D and explain the reactions involved.
Answer:
1. (A) is identified as CH₃CONH₂ acetarnide.

2. Acetamide on reaction with P₂O₅ gives methyl cyanide as (B)

3. Methyl cyanide on acid hydrolysis gives acetic acid CH₃COOH as (C)

4. Acetic acid on reaction with LiAlH₄ gives ethanol as (D)

Errors

Aldehydes IUPAC names
Ketone – IUPAC name
Ozonolysis – easy way to remember the products. Students may feel difficult in writing equation
Clemmenson reduction and Wolf – Kishner reduction may get confused

Rectifications

1. The name should end with the word – al, HCHO – methanal, Aldehyde – Al, Alcohol – ol

2. The name should end with the word – one. Propanone

3. By the either side of = bond, add one oxygen atom as products

4. The products are same, only catalyst are different

Tamilnadu Samacheer Kalvi 12th Chemistry Solutions Chapter 12 Carbonyl Compounds and Carboxylic Acids

Samacheer Kalvi 12th Chemistry Chapter 12 Carbonyl Compounds and Carboxylic Acids Text Book Evaluation

Samacheer Kalvi 12th Chemistry Carbonyl Compounds and Carboxylic Acids Additional Questions

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