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 8 of 34
- A. HCHO
- B. CH3CHO
- C. CH3COCH3
- D. C6H5CHO
Explanation: Tertiary alkyl groups are less reactive because they are surrounded by alkyl groups, making them more stable and least reactive.
Correct answer: CH3COCH3- A. sp hybridized
- B. sp2 hybridized
- C. sp3 hybridized
- D. None of these
Explanation: Organic compounds containing the carbonyl functional group, are called carbonyl compounds.
Correct answer: sp2 hybridized143. Formalin is:
- A. 10% solution of formaldehyde in water + 8% methyl alcohol
- B. 20% solution of formaldehyde in water + 8% methyl alcohol
- C. 40% solution of formaldehyde in water + 8% methyl alcohol
- D. 60% solution of formaldehyde in water + 8% methyl alcohol
Explanation: Formalin is a mixture of 40 % formaldehyde, 8% methyl alcohol and 52 % water.
Correct answer: 40% solution of formaldehyde in water + 8% methyl alcohol- A. Electrophilic addition
- B. Electrophilic substitution
- C. Nucleophilic addition
- D. Nucleophilic substitution
Explanation: "As CN is a nucleophile, it is added to acetaldehyde by donating electrons.
Correct answer: Nucleophilic addition- A. Acetaldehyde
- B. Propanaldehyde
- C. Formaldehyde
- D. Trideuteroacetaldehyde
Explanation: The aldehydes that have alpha hydrogen atoms undergo aldol condensation reaction
Correct answer: Formaldehyde- A. Alkaline Iodine
- B. Tollen's Reagent
- C. Bromine
- D. 2, 4 DNPH
Explanation: The Tollens' test is a reaction that is used to distinguish aldehydes from ketones, as aldehydes are able to be oxidized into a carboxylic…
Correct answer: Tollen's Reagent- A. Aldehydes
- B. Primary Alcohols
- C. Secondary Alcohols
- D. Tertiary Alcohols
Explanation: Option A; aldehydes oxidize into carboxylic acids.Option B; primary alcohols oxidize into aldehydes and then to carboxylic acids.Option C…
Correct answer: Secondary Alcohols- A. LiAlH4
- B. Zn(Hg)-HCl
- C. NaBH4
- D. CH3MgI
Explanation: The reaction is Clemmensen reduction. The reaction of aldehydes and ketones with zinc amalgam (Zn/Hg alloy) in concentrated hydrochloric…
Correct answer: Zn(Hg)-HCl- A. Ethanol
- B. Ethanal
- C. Acetophenone
- D. Benzophenone
Explanation: The reaction of iodine and base with methyl ketones is called the "iodoform test". It is used to probe the presence of a methyl ketone.
Correct answer: Benzophenone- A. Electrophilic addition reaction
- B. Substitution reaction
- C. Nucleophilic addition reaction
- D. Displacement reaction
Explanation: The given scenario is an example of a nucleophilic addition reaction, as the reactant, CN- is a nucleophile which adds across the carbonyl…
Correct answer: Nucleophilic addition reaction- A. In alcohol with CHI3
- B. In alcohol with I2
- C. In ethanol and water mixture with KI and I2
- D. In KI and CH3I
Explanation: 'Tincture of iodine' is a weak solution of iodine which is used as an antiseptic.
Correct answer: In ethanol and water mixture with KI and I2- A. R-OH
- B. R-COOH
- C. R-CO-R
- D. R-X
- E. R-CHO
Explanation: Aldehydes and ketones have a carbonyl group (C=O) as a functional group.
Correct answer: R-CHO- A. CH3 CH2COOCH2C2H5
- B. CH3 CH2 CHOH CH2 CH2 CHO
- C. CH3 CH2 CH (OH) CH(CH3) CHO
- D. CH3 CH2 COCH2 CH2 CHO
Explanation: When propionaldehyde (CH3CH2CHO) reacts with a dilute NaOH (sodium hydroxide) solution, it undergoes a nucleophilic addition reaction…
Correct answer: CH3 CH2 CH (OH) CH(CH3) CHO- A. CHCl3
- B. Cl3CCHO
- C. CCl4
- D. ClCH2CH2Cl
Explanation: Cl3CCHO will react with water. Water is a polar solvent. Like dissolves like.
Correct answer: Cl3CCHO- A. Alcohols
- B. Esters
- C. Cyanides
- D. Ethers
- E. Aldehydes
Explanation: The general formula ROR is indicative of ethers, which consist of two alkyl or aryl groups linked by an oxygen atom.
Correct answer: Ethers- A. Reaction with HCN
- B. Reaction with Fehling solution
- C. Reaction with NaHSO3
- D. Reaction with 2,4-dinitrophenyl-hydrazine
Explanation: Fehling's solution is a mixture of Rochelle salt (blue color) and copper sulphate (chso4).
Correct answer: Reaction with Fehling solution- A. α - Methyl - Ɣ - Chloro Propionaldehyde
- B. β - Chloro - Ɣ - Methyl - Propionaldehyde
- C. β - Chloro - α - Methyl Propionaldehyde
- D. β - Methyl - α - Chloro Propionaldehyde
Explanation: Aldehydes take their name from their parent alkane chains. The -e is removed from the end and is replaced with -al.
Correct answer: β - Chloro - α - Methyl Propionaldehyde- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: Reduction of ketones gives secondary alcohols. The acidic work-up converts an intermediate metal alkoxide salt into the desired alcohol…
Correct answer: Option A- A. Tertiary alcohol
- B. Isopropyl alcohol
- C. Primary alcohol
- D. Carboxylic acid
Explanation: The correct answer is a tertiary alcohol. When a ketone, which has a carbonyl group (C=O) bonded to two carbon-containing groups, reacts…
Correct answer: Tertiary alcohol- A. Alkylation of benzene
- B. Acylation of benzene
- C. Oxidation of benzene
- D. Halogenation of benzene
- E. Both A and B
Explanation: Since the acyl group is added to the benzene as a result of this reaction process we can say that it is an acylation of benzene.
Correct answer: Acylation of benzene