Free Aldehydes and Ketones MCQs with Answers

• A. Aldehydes are easily oxidized while ketones do not
• B. Aldehydes show position isomerism while ketones do not
• C. Aldehydes can be oxidized easily by Fehling's solution while ketones do not
• D. Aldehydes react with alcohols to form acetal while ketones do not

Explanation: This statement is incorrect. Both aldehydes and ketones can exhibit position isomerism.

• A. Sod. nitropusside test
• B. Tollen's reagent test
• C. Fehling's solution test
• D. Benedict's reagent test

Explanation: Option A is correct.Sodium nitroprusside test is shown by ketones only.

• A. Ethanal
• B. Secondary alcohols
• C. Methyl ketone
• D. Methanol

Explanation: Option D is correct.Methanol (CH3OH) does not give iodoform test. The iodoform test is a chemical test used to detect the presence of…

• A. H2/Ni
• B. LiAIH4
• C. N2H2/KOH
• D. NaBH4

Explanation: Option C is correct.N2H2/KOH is a reducing agent that is often used to reduce aldehydes to amines.

• A. Methanal
• B. Ethanal
• C. Butanal
• D. Propanal

Explanation: Option A is correct.Methanal is the simplest aldehyde and has no alkyl groups. This makes it the most reactive aldehyde.

• A. Butanone
• B. 2-Pentanone
• C. 2-Hexanone
• D. 3-Pentanon

Explanation: Option D is correct.Only 3-pentanone does not give the iodoform test. The iodoform test is a chemical test used to detect the presence of…

• A. Nucleophilic addition
• B. Nucleophilic substitution
• C. Electrophilic addition
• D. Addition-elimination

Explanation: Option D is correct.Yes, the reaction of aldehydes and ketones with ammonia derivatives is known as addition-elimination.

• A. Increases nucleophilic character of attacking reagent
• B. Increases electrophilic character of carbon of carbonyl group
• C. Increases both electrophilic and nucleophilic character
• D. Has no effect on the reactivity of carbonyl groups

Explanation: Option B is correct.The nucleophilic addition reactions of carbonyl groups are catalyzed by bases or acids.

• A. Nucleophilic addition reaction
• B. Reduction reaction
• C. β-Elimination reaction
• D. Oxidation reaction

Explanation: Option Cis correct.β-Elimination reaction is a reaction in which a hydrogen atom and a halogen atom are removed from adjacent carbon atoms…

• A. 1o alcohol on oxidation gives aldehyde
• B. 2o alcohol on oxidation gives ketone
• C. On dry distillation of calcium methanoate, ethanol is produced
• D. On dry distillation of calcium ethanoate, propanone is produced

Explanation: Option C is correct.No, on dry distillation of calcium methanoate, acetaldehyde is produced. The reaction is called dry distillation.

• A. Anywhere in the carbon chain
• B. In the middle of carbon chain
• C. Only at the second carbon atom of the carbon chain
• D. Only at the terminal carbon atom of the carbon chain

Explanation: Aldehydes can only occur at terminal carbon and not anywhere in Carbon chain.

• A. Reducing agent only
• B. Oxidizing agent only
• C. Both A and B
• D. Neither A nor B

Explanation: Aldehyde reduces Cu(oh)2 to Cu2O, we know so by calculating the oxidation state of Cu which changes from +2 to +1.

• A. Base catalyzed only
• B. Acid catalyzed only
• C. Both A and B
• D. Neither A nor B

Explanation: Option B is correct. It is an acid catalyzed reaction because as the H+ eliminates from the acid it combines with carbonyl oxygen to…

• A. Aldehyde
• B. 1o alcohol
• C. ketones
• D. 2o alcohol

Explanation: Amongst all the options given, Ketones are the most difficult to oxidize ,they are only oxidized by strong oxidizing agents.

• A. CH3CH2COOH only
• B. CH3-CH2-COOH and CH3COOH
• C. CH3COOH only
• D. CH3COOH and HCOOH

Explanation: Option B is correct. Pent-2-one is a unsymmetrical carbonyl compound, so upon being oxidized it will give us a mixture of products such as…

• A. An aldehyde can be represented by general formula (R-C-H)
• B. A ketone can be represented by general formula (R-C-R' )
• C. Ketone group is present in camphor and menthone
• D. The homologous series of both aldehydes and ketones have generalformula Cₙ H2nO

Explanation: Amongst the four given options , the incorrect one is A. An aldehyde is generally represented by RCHO .

• A. Benzene
• B. Ammonia
• C. Phenol
• D. Hydrocarbon

Explanation: C is correct. Methanal reacts with phenol to give hydroxy benzyl alcohol which on further reaction with phenol gives polymer Bakelite.

• A. Position isomerism
• B. Functional group isomerism
• C. Metamerism
• D. Tatoumerism

Explanation: Aldehydes and ketones both have same molecular formulae just different functional group and hence shows functional group isomerism.

• A. Option A
• B. Option B
• C. Option C
• D. Option D

Explanation: Aliphatic aldehydes react with bendict solution to form brick red ppt and thus are used to differentiate aldehydes from ketones as ketones…

• A. Option A
• B. Option B
• C. Option C
• D. Option D

Explanation: The reaction is carried out with 50 percent aqueous solution of sodium hydroxide at room temperature.