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12th Class Chemistry Chapter 12 MCQs with Answers

12th Class Chemistry Chapter 12 MCQs

Master Aldehydes and Ketones with our 12th Class Chemistry Chapter 12 MCQs. Practice oxidation, reduction, and addition reactions. Trending keywords like aldehydes quiz, ketones MCQs, and chemistry organic reactions ensure superior rankings and preparation.

Aldehydes and ketones are organic compounds containing which functional group?
a) Alcohol group (OH)
b) Carboxylic acid group (COOH)
c) Carbonyl group (C=O)
d) Amine group (NH2)

Answer
c) Carbonyl group (C=O)

Which of the following is the general formula for aldehydes?
a) R-CO-R
b) R-OH
c) R-CO-H
d) R-CO-OR

Answer
c) R-CO-H

Which of the following is the general formula for ketones?
a) R-CO-R
b) R-OH
c) R-CO-H
d) R-CO-OR

Answer
a) R-CO-R

Aldehydes and ketones are characterized by the presence of the carbonyl group, which is a combination of:
a) Carbon and hydrogen
b) Carbon and oxygen
c) Carbon and nitrogen
d) Carbon and sulfur

Answer
b) Carbon and oxygen

In an aldehyde, the carbonyl group is always located at the:
a) End of the carbon chain
b) Middle of the carbon chain
c) Anywhere in the carbon chain
d) Attached to a nitrogen atom

Answer
a) End of the carbon chain

In a ketone, the carbonyl group is always located at the:
a) End of the carbon chain
b) Middle of the carbon chain
c) Anywhere in the carbon chain
d) Attached to a nitrogen atom

Answer
b) Middle of the carbon chain

Which of the following functional groups is present in both aldehydes and ketones?
a) Hydroxyl group (OH)
b) Carbonyl group (C=O)
c) Carboxyl group (COOH)
d) Amino group (NH2)

Answer
b) Carbonyl group (C=O)

Which of the following is the simplest aldehyde?
a) Methanal
b) Ethanal
c) Propanal
d) Butanal

Answer
a) Methanal

Which of the following is the simplest ketone?
a) Methanone
b) Ethanone
c) Propanone
d) Butanone

Answer
a) Methanone

Which of the following compounds is an aldehyde?
a) Acetone
b) Formaldehyde
c) Acetophenone
d) Benzophenone

Answer
b) Formaldehyde

Which of the following compounds is a ketone?
a) Acetone
b) Formaldehyde
c) Acetophenone
d) Benzophenone

Answer
a) Acetone

Which of the following compounds is an aldehyde?
a) Benzaldehyde
b) Acetone
c) Acetophenone
d) Acetaldehyde

Answer
a) Benzaldehyde

Which of the following compounds is a ketone?
a) Benzaldehyde
b) Acetone
c) Acetophenone
d) Acetaldehyde

Answer
c) Acetophenone

What is the IUPAC name for CH3CHO?
a) Ethanol
b) Ethanoic acid
c) Ethanal
d) Ethanoate

Answer
c) Ethanal

What is the IUPAC name for CH3COCH3?
a) Acetic acid
b) Propanone
c) Ethanol
d) Ethanoate

Answer
b) Propanone

Which of the following reagents can be used to distinguish between aldehydes and ketones?
a) Fehling’s solution
b) Benedict’s solution
c) Tollen’s reagent
d) Both A and C

Answer
d) Both A and C

Fehling’s solution is used to test for the presence of:
a) Aldehydes
b) Ketones
c) Alcohols
d) Carboxylic acids

Answer
a) Aldehydes

Tollen’s reagent is used to test for the presence of:
a) Aldehydes
b) Ketones
c) Alcohols
d) Carboxylic acids

Answer
a) Aldehydes

Which of the following compounds will give a positive Fehling’s test?
a) Benzaldehyde
b) Acetone
c) Propanal
d) Acetophenone

Answer
a) Benzaldehyde

Which of the following compounds will give a positive Tollen’s test?
a) Benzaldehyde
b) Acetone
c) Propanal
d) Acetophenone

Answer
a) Benzaldehyde

Aldehydes can be oxidized to form:
a) Alcohols
b) Ketones
c) Carboxylic acids
d) Esters

Answer

Which of the following is a product of the oxidation of an aldehyde?
a) Alcohol
b) Ketone
c) Carboxylic acid
d) Ester

Answer
c) Carboxylic acid

Which of the following reagents can be used to oxidize an aldehyde to a carboxylic acid?
a) KMnO4
b) NaBH4
c) LiAlH4
d) H2SO4

Answer
a) KMnO4

Which of the following reagents can be used to reduce a ketone to an alcohol?
a) KMnO4
b) NaBH4
c) LiAlH4
d) H2SO4

Answer
c) LiAlH4

Which of the following compounds undergoes keto-enol tautomerism?
a) Aldehydes
b) Ketones
c) Carboxylic acids
d) Esters

Answer
b) Ketones

Keto-enol tautomerism involves the interconversion between the keto form and the enol form, where the enol form contains:
a) A carbonyl group
b) A double bond
c) An alcohol group
d) An aldehyde group

Answer
c) An alcohol group

The enol form of a compound contains:
a) A carbonyl group
b) A double bond
c) An alcohol group
d) An aldehyde group

Answer
c) An alcohol group

The keto form of a compound contains:
a) A carbonyl group
b) A double bond
c) An alcohol group
d) An aldehyde group

Answer
a) A carbonyl group

Which of the following is an example of keto-enol tautomerism?
a) Acetone ⇌ Acetaldehyde
b) Acetone ⇌ Ethanol
c) Ethanol ⇌ Ethyl acetate
d) Acetaldehyde ⇌ Ethanol

Answer
b) Acetone ⇌ Ethanol

Which of the following compounds will show keto-enol tautomerism?
a) Acetone
b) Benzaldehyde
c) Propanone
d) Ethanal

Answer
a) Acetone

Which of the following is an example of intramolecular keto-enol tautomerism?
a) Ethanol ⇌ Ethyl acetate
b) Acetone ⇌ Acetaldehyde
c) Propanone ⇌ Prop-2-en-2-ol
d) Methanol ⇌ Methyl acetate

Answer
c) Propanone ⇌ Prop-2-en-2-ol

The process of converting an aldehyde or ketone to a geminal diol is called:
a) Hydrogenation
b) Halogenation
c) Hydration
d) Reduction

Answer
c) Hydration

The process of converting an aldehyde or ketone to an acetal or ketal is called:
a) Hydrogenation
b) Halogenation
c) Hydration
d) Acetalization

Answer
d) Acetalization

Which of the following is a product of the reaction between an aldehyde or ketone with an alcohol in the presence of an acid catalyst?
a) Acetal
b) Ketal
c) Ester
d) Ether

Answer
a) Acetal

Which of the following is a product of the reaction between an aldehyde or ketone with two alcohol molecules in the presence of an acid catalyst?
a) Acetal
b) Ketal
c) Ester
d) Ether

Answer
b) Ketal

Which of the following reagents can be used to convert an aldehyde to its corresponding geminal diol?
a) H2SO4
b) H2O
c) NaBH4
d) H2/Pt

Answer
b) H2O

Which of the following reagents can be used to convert an aldehyde to its corresponding acetal?
a) H2SO4
b) H2O
c) NaBH4
d) CH3OH

Answer
d) CH3OH

The process of converting an acetal or ketal back to the original aldehyde or ketone is called:
a) Hydrolysis
b) Reduction
c) Dehydration
d) Oxidation

Answer
a) Hydrolysis

Which of the following is a product of the hydrolysis of an acetal or ketal?
a) Alcohol
b) Aldehyde or ketone
c) Carboxylic acid
d) Ester

Answer
b) Aldehyde or ketone

Which of the following compounds can undergo nucleophilic addition reactions at the carbonyl group?
a) Aldehydes
b) Ketones
c) Carboxylic acids
d) Esters

Answer
a) Aldehydes

The nucleophilic addition reaction at the carbonyl group of an aldehyde or ketone involves the addition of a nucleophile to the:
a) Carbon atom of the carbonyl group
b) Oxygen atom of the carbonyl group
c) Hydrogen atom of the carbonyl group
d) Double bond of the carbonyl group

Answer
a) Carbon atom of the carbonyl group

Which of the following nucleophiles can react with aldehydes and ketones?
a) Hydrogen cyanide (HCN)
b) Sodium hydroxide (NaOH)
c) Ammonia (NH3)
d) All of the above

Answer
d) All of the above

The reaction between an aldehyde or ketone and hydrogen cyanide (HCN) is called:
a) Cyanation
b) Hydrolysis
c) Reduction
d) Cyanohydrin formation

Answer
d) Cyanohydrin formation

Which of the following compounds is a cyanohydrin?
a) Acetonitrile
b) Acetone cyanohydrin
c) Acetic acid
d) Acetaldehyde

Answer
b) Acetone cyanohydrin

The reaction between an aldehyde or ketone and an alcohol in the presence of an acid catalyst is called:
a) Esterification
b) Hydration
c) Acetalization
d) Cyanohydrin formation

Answer
c) Acetalization

Which of the following is a product of the reaction between an aldehyde or ketone with an alcohol in the presence of an acid catalyst?
a) Ester
b) Ether
c) Acetal
d) Ketal

Answer
c) Acetal

The reaction between an aldehyde or ketone and ammonia (NH3) is called:
a) Cyanation
b) Hydrolysis
c) Reduction
d) Formation of imines

Answer
d) Formation of imines

Which of the following compounds is an imine?
a) Acetonitrile
b) Acetone
c) Acetaldehyde
d) Butanone

Answer
c) Acetaldehyde

The reaction between an aldehyde or ketone with a primary amine is called:
a) Cyanation
b) Hydrolysis
c) Reduction
d) Formation of Schiff bases

Answer
d) Formation of Schiff bases

Which of the following compounds is a Schiff base?
a) Acetonitrile
b) Acetone
c) Acetaldehyde
d) Butanone

Answer
c) Acetaldehyde

The reaction between an aldehyde or ketone with a secondary amine is called:
a) Cyanation
b) Hydrolysis
c) Reduction
d) Formation of enamines

Answer
d) Formation of enamines

Which of the following compounds is an enamine?
a) Acetonitrile
b) Acetone
c) Acetaldehyde
d) Butanone

Answer
d) Butanone

The reaction between an aldehyde or ketone with a Grignard reagent is called:
a) Cyanation
b) Hydrolysis
c) Reduction
d) Formation of alcohol

Answer
d) Formation of alcohol

Which of the following is a product of the reaction between an aldehyde or ketone with a
Grignard reagent?
a) Alcohol
b) Ether
c) Aldehyde
d) Ketone

Answer
a) Alcohol

Which of the following reagents can be used to distinguish between aldehydes and ketones?
a) Tollen’s reagent
b) Fehling’s solution
c) Schiff’s reagent
d) Both A and B

Answer
d) Both A and B

The reaction between an aldehyde and Tollens’ reagent results in the formation of a:
a) Silver mirror
b) Green precipitate
c) Red precipitate
d) White precipitate

Answer
a) Silver mirror

The reaction between a ketone and Tollens’ reagent does not give a positive test
because:
a) Ketones do not contain a carbonyl group
b) Ketones are unable to undergo nucleophilic addition reactions
c) Ketones do not have an alpha hydrogen atom
d) Ketones do not contain a silver ion

Answer
c) Ketones do not have an alpha hydrogen atom

Which of the following is the major product obtained when an aldehyde is heated with excess alcohol in the presence of an acid catalyst?
a) Acetal
b) Hemiacetal
c) Ketal
d) Hemiketal

Answer
a) Acetal

Which of the following is the major product obtained when a ketone is heated with excess alcohol in the presence of an acid catalyst?
a) Acetal
b) Hemiacetal
c) Ketal
d) Hemiketal

Answer
c) Ketal

The functional group of an aldehyde or ketone is a(n):
a) Alcohol group
b) Carbonyl group
c) Carboxylic acid group
d) Amine group

Answer
b) Carbonyl group

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