CBSE Class 12 Chemistry Aldehydes Ketones And Carboxylic Acids Question Bank Set B

Question. Which of the following compounds will give butanone on oxidation with alkaline KMnO₄ solution ?
(A) Butan-1-ol
(B) Butan-2-ol
(C) Both of these
(D) None of these
Answer : B

Question. Write the IUPAC name of
CH₃—CH₂—CHO
            |
         NH₂
(A) 1-Aminopropanaldehyde
(B) 2-Aminopropanal
(C) 1-Aminoethan-1-al
(D) None of the above 
Answer : B

Question. What kind of compounds undergo Cannizzaro reaction?
(A) Ketones with no α- hydrogen
(B) Aldehydes with α- hydrogen
(C) Carboxylic acids with α- hydrogen
(D) Aldehydes with no α- hydrogen 
Answer : D

Question. Write the product(s) in the following reactions:

Answer : B

Question. Compounds A and C in the following reaction are

(A) identical
(B) positional isomers
(C) functional isomers
(D) optical isomers
Answer : B

Question. In Clemmensen reduction, carbonyl compound is treated with _________.
(A) zinc amalgam + HCl
(B) sodium amalgam + HCl
(C) zinc amalgam + nitric acid
(D) sodium amalgam + HNO₃ 
Answer : A

Question. The reagent which does not react with both, acetaldehyde and benzaldehyde.
(A) Sodium hydrogen sulphite
(B) Phenyl hydrazine
(C) Fehling’s solution
(D) Grignard reagent
Answer : C

Question. C₆H₅ – CO – CH₃ NaOH/I₂ ? + ?
(A) C₆H₅COOH + CH₄
(B) C₆H₅COONa + CHI₃
(C) C₆H₆ + CH₃COONa + HI
(D) C₆H₅CH₂COOH
Answer : B

Question. Predict the product of the following reaction:

(A) CH₃CH₂CH₃
(B) CH₃CHOHCH₃
(C) CH₃CH₂CHO
(D) CH₃CONHCH₃
Answer : A

Question. Which of the following compounds is most reactive towards nucleophilic addition reactions ?

Ans. Option (A) is correct.

Question. Formaldehyde reacts with methyl magnesium bromide followed by hydrolysis to form:
(A) Methanol
(B) Ethanol
(C) Propanol
(D) Butanol
Answer : B

Question. Common name of Ethane-1,2-dioic acid is known as:
(A) Oxalic acid
(B) Phthalic acid
(C) Adipic acid
(D) Acetic acid R
Answer : A

Question. The carboxylic acid that does not undergo HVZ reaction is:
(A) CH₃COOH
(B) (CH₃)₂CHCOOH
(C) CH₃CH₂CH₂CH₂COOH
(D) (CH₃)₃CCOOH
Answer : D

Question. Which of the following acids does not form anhydride ?
(A) Formic acid
(B) Acetic acid
(C) Propionic acid
(D) n-butyric acid
Answer : A

Question. Which of the following is the strongest acid?
(A) Acetic acid
(B) Phenol
(C) Methyl alcohol
(D) Water 
Answer : A

Question. The reaction in which the aqueous solution of sodium salt of carboxylic acids on electrolysis give alkanes:
(A) Soda lime decarboxylation
(B) Kolbe’s electrolysis decarboxylation
(C) Dry distillation of calcium formate
(D) Reduction of carboxylic acid. 
Answer : B

Question. Arrange the following compounds in increasing order of acid strength

(A) (i) > (ii) > (iii)
(B) (ii) < (i) < (iii)
(C) (iii) < (i) < (ii)
(D) (iii) > (i) > (ii)
Answer : C

Question. Complete the following reaction:

Answer : C

Question. Identify the name of the given reaction:

(A) Etard reaction
(B) Hell-Volhard-Zelinsky reaction
(C) Stephen reaction
(D) None of the above
Answer : B

Assertion and Reason Based MCQs

Directions: In the following questions, a statement of Assertion (A) is followed by a statement of Reason (R).
Mark the correct choice as:
(A) Both (A) and (R) are true, and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is NOT the correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.

Question. Assertion (A): Oxidation of ketones is easier than aldehydes.
Reason (R): C–C bond of ketones is stronger than C–H bond of aldehydes.
Answer : D

Question. Assertion (A): Benzaldehyde is less reactive than ethanal towards nucleophilic addition reactions.
Reason (R): Ethanal is more sterically hindered.
Answer : B

Question. Assertion (A): Aromatic aldehydes and formaldehyde undergo Cannizzaro reaction.
Reason (R): Aromatic aldehydes are almost as reactive as formaldehyde. 
Answer : C

Question. Assertion (A): Aldehydes and ketones, both react with Tollen’s reagent to form silver mirror.
Reason (R): Both aldehydes and ketones contain a carbonyl group. 
Answer : D

Question. Assertion (A): Benzoic acid does not undergo Friedel-craft’s reaction.
Reaction (R): The carboxyl group is activating group and undergo electrophilic substitution reaction.
Answer : C

Question. Assertion (A): Compounds containing —CHO group are easily oxidised to corresponding carboxylic acids.
Reason (R): Carboxylic acids can be reduced to alcohols by treatment with LiAlH4.
Answer : B

Question. Assertion (A): Aromatic carboxylic groups do not undergo Friedel- Crafts reaction.
Reason (R): Carboxyl group is deactivating and the catalyst aluminium chloride gets bonded to the carboxyl group. 
Answer : A

Question. Assertion (A): Carboxylic acids are more acidic than phenols.
Reason (R): Phenols are ortho and para directing.
Answer : B

Case-based MCQs

I. Read the passage given below and answer the following questions: 
Carboxylic acids having an a-hydrogen atom when treated with chlorine or bromine in the presence of small amount of red phosphorus gives a-halocarboxylic acids. The reaction is known as Hell-Volhard-Zelinsky reaction.

In the following questions, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices on the basis of the above passage.
(A) Assertion and reason both are correct statements and reason is correct explanation for assertion.
(B) Assertion and reason both are correct statements but reason is NOT correct explanation for assertion.
(C) Assertion is correct statement but reason is wrong statement.
(D) Assertion is wrong statement but reason is correct statement.

Question. Assertion (A): (CH₃)₃CCOOH does not give H.V.Z. reaction.
Reason (R): (CH₃)₃CCOOH does not have a-hydrogen atom
Answer : A

Question. Assertion (A): H.V.Z. reaction involves the treatment of carboxylic acids having a-hydrogens with Cl₂ or Br₂ in presence of small amount of red phosphorus.
Reason (R): Phosphorus reacts with halogens to form rhosphorus trihalides.
Answer : C

Question. Assertion (A): C₆H₅COCH₂COOH undergoes decarboxylation easily than C6H₅COCOOH.
Reason (R): C₆H₅COCH₂COOH is a b-keto acid.
Answer : A

Question. Assertion (A): On heating 3-methylbutanoic acid with soda lime, isobutane is obtained.
Reason (R): Soda lime is a mixture of NaOH + CaO in the ratio 3:1.
Answer : B

II. Read the passage given below and answer the following questions:
Aldehydes, ketones and carboxylic acids are few of the major classes of organic compounds containing carbonyl group. Aldehydes are prepared by dehydrogenation or controlled oxidation of primary alcohols and controlled or selective reduction of acyl halides. Ketones are prepared by oxidation of secondary alcohols and hydration of alkynes Carboxylic acids are prepared by the oxidation of primary alcohols, aldehydes and alkenes by hydrolysis of nitriles and by treatment of Grignard reagents with carbon dioxide.

Question. Name a method by which both aldehydes and ketones can be prepared.
(A) Reduction of carboxylic acids
(B) Ozonolysis of alkenes
(C) Oxidation of alcohols
(D) All of the above
Answer : D

Question. How will you distinguish between aliphatic aldehydes and aromatic aldehydes ?
(A) Fehling’s test
(B) Benedict’s test
(C) Iodoform test
(D) Hinsberg reagent
Answer : A

Question. Name the main compounds A and B formed in the following reaction:

(A) CH₃CH₂COOH [A], CH₃CH₂CH₃ [B]
(B) CH₃CH₂CHO [A], C₂H₄ [B]
(C) CH₃COCH₃ [A], CH₃CH₂CH₃ [B]
(D) CH₃COCH₃ [A], C₂H₆ [B]
Answer : C

Question. The reagent which does not react with both, acetone and benzaldehyde.
(A) Sodium hydrogensulphite
(B) Phenyl hydrazine
(C) Fehlings’ solution
(D) Grignard reagent
Answer : C

Question. Through which of the following reactions number of carbon atoms can be increased in the chain?
(A) Grignard reaction
(B) Cannizzaro reaction
(C) Clemmenson reduction
(D) HVZ reaction
Answer : A

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