Free Aldehydes and Ketones MCQs with Answers
679 Aldehydes and Ketones MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Aldehydes and ketones contain the polar carbonyl group, but aldehydes are generally more readily oxidised and more reactive than ketones. Coverage includes preparation by oxidation or reduction routes, nucleophilic addition of reagents such as hydrogen cyanide and bisulfite, and tests that distinguish aldehydes from ketones.
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679 questions · page 9 of 34
- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: Ozonolysis of alkene: Ozonolysis is a method of oxidatively cleaving alkenes or alkynes using ozone (O3), a reactive allotrope of oxygen.
Correct answer: Option C- A. sp
- B. sp2
- C. sp3
- D. dsp
Explanation: In the CHO group, - HC=O, the carbon is double bonded to an oxygen and single bonded to hydrogen and another R group, which may be an…
Correct answer: sp2- A. Electrophilic addition reaction
- B. Nucleophilic addition reaction
- C. Electrophilic substitution reaction
- D. Nucleophilic substitution reaction
Explanation: t, the carbonyl group (C=O) undergoes nucleophilic addition reactions rather than electrophilic addition reactions.
Correct answer: Nucleophilic addition reaction- A. Nucleophilic addition reaction
- B. Unimolecular Nucleophilic substitution reaction
- C. Electrophilic substitution reaction
- D. Bimolecular Nucleophilic substitution reaction
- E. Nucleophilic elimination reaction
Explanation: A cyanohydrin reaction is an organic chemical reaction by an aldehyde or ketone with a cyanide anion or a nitrile to form a…
Correct answer: Nucleophilic addition reaction- A. Iodoform test
- B. Schiff's test
- C. Benedict's reagent test
- D. Tollen's test
- E. Cannizzaro's test
Explanation: When methyl ketone is heated with iodine in the presence of sodium hydroxide, yellow precipitate of iodoform is obtained.Hence, methyl…
Correct answer: Iodoform test- A. Esters
- B. Ethers
- C. Aldehydes
- D. Ketones
Explanation: Ethers functional group is an oxygen atom singly bonded to two alkyl or aryl groups or chains R-O-R.
Correct answer: Ethers- A. Sp2
- B. Sp3
- C. Sp
- D. dsp2
Explanation: In aldehydes, the geometry around the carbon atom in the carbonyl group is trigonal planar; the carbon atom exhibits sp2 hybridization.
Correct answer: Sp2- A. Electrophilic
- B. Nucleophilic
- C. Electron deficient
- D. All of these
Explanation: The carbonyl carbon is an electrophilic (lewis acid) and carbonyl oxygen is, a nucleophilic (lewis base) centre.
Correct answer: All of these- A. Beta hydroxy carboxylic acid
- B. Alpha hydroxy carboxylic acid
- C. Carboxylic acid
- D. Unsaturated acid
Explanation: The hydrolysis of cyanohydrin gives alpha hydroxy. carboxylic acids. In the above reaction, the cyano group is hydrolyzed to a carboxylic…
Correct answer: Alpha hydroxy carboxylic acid- A. Aldehyde
- B. Alcohol
- C. Esters
- D. Ketones
Explanation: Remember that when naming ketones, we end the name with -one and since menthone has -one, it can be concluded that it belongs to the group…
Correct answer: Ketones- A. Nucleophilic
- B. Electrophilic
- C. Neutral
- D. all of these
Explanation: Carbon attached to the aldehyde group is electron deficient due to highly electronegative oxygen being bonded to it, thus acting as an…
Correct answer: Electrophilic- A. Acidified Potassium hydroxide
- B. Acidified Potassium dichromate (VI)
- C. Acidified Phosphoric acid
- D. Acidified Oxalic acid
Explanation: The reaction above is oxidation of a secondary alcohol into a ketone. As such, an oxidizing agent must be chosen for reagent X.
Correct answer: Acidified Potassium dichromate (VI)- A. X = Aldehyde O = Silver mirror
- B. X = Ketone, O = Grey precipitate
- C. X = Ketone, O = Silver mirror
- D. X = Aldehyde O = Red precipitate
Explanation: Tollens reagent test is also known as the silver mirror test. It cannot react with ketones but it reacts with aldehydes, thereby…
Correct answer: X = Aldehyde O = Silver mirror- A. Tertiary alcohols
- B. Carboxylic acids
- C. Aldehydes
- D. Ketones
Explanation: Only aldehydes can be easily oxidised by mild oxidising agents such as the Tollen reagent, Fehling solution and Benedict solution.
Correct answer: Aldehydes- A. Butanal
- B. Methanal
- C. Ethanal
- D. All of these options are correct
Explanation: The silver mirror test is mainly used for testing the aldehyde compounds.
Correct answer: All of these options are correct- A. Acetylides
- B. Paraldehyde
- C. Bakelite
- D. Meta Acetaldehyde
Explanation: In the presence of concentrated H2SO4, Acetaldehyde is polymerized to Paraldehyde.Acetaldehyde + conc. H2SO4 = paraldehyde
Correct answer: Paraldehyde- A. Ethene
- B. Ethanol
- C. Ethanoic acid
- D. Ethanone
Explanation: Aldehyde when undergoes oxidation reaction in presence of acidified potassium dichromate or alkaline potassium permanganate forms…
Correct answer: Ethanoic acid- A. Electrophilic addition
- B. Electrophilic substitution
- C. Free radical substitution
- D. Nucleophilic addition
Explanation: The main reactions of the carbonyl group are nucleophilic additions to the carbon‐oxygen double bond.
Correct answer: Nucleophilic addition- A. Dehydration
- B. Polymerization
- C. Aldol Condensation
- D. Oxidation reaction
Explanation: In the presence of concentrated H2SO4, acetaldehyde primarily undergoes polymerization to form paraldehyde.
Correct answer: Polymerization- A. Propyne
- B. Secondary alcohol
- C. Calcium acetate
- D. All of these
Explanation: Each of the given options,propyne, secondary alcohols, and calcium acetate-can undergo specific reactions leading to the formation of…
Correct answer: All of these