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 19 of 34
- A. 2-propanol
- B. I-Butonal
- C. 2-Butanol
- D. Teritary butyl alcohol
Explanation: Methyl ethyl ketone is a 4-C ketone. So, it requires a 4-C secondary alcohols
Correct answer: 2-Butanol- A. Reduction
- B. Substitution
- C. Oxidation
- D. Elimination
Explanation: This reaction is involving oxidation of ethanol.
Correct answer: Oxidation- A. - CH3 is oxidized to CH2-OH
- B. - OH is oxidized to-CO group
- C. >CH2 is oxidized to -CHO group
- D. -CH2OH is oxidized to -CHO
Explanation: Explanation is given as: During the oxidation of ethanol to ethanal, the carbon atom (CH2) adjacent to the hydroxyl group (OH) in ethanol…
Correct answer: >CH2 is oxidized to -CHO group- A. Aldehydes
- B. Ketones
- C. Pure alcohols only
- D. Both A and B.
Explanation: The aldehydes and ketones give yellow or orange colour crystals (2,4-dinitrophenylhydrozone)
Correct answer: Both A and B.365. Addition of HCN to acetaldehyde in the presence of dilute mineral acid and sodium cyanide forms
- A. Formaldehyde cyanohydrin
- B. Acetaldehyde cyanohydrin
- C. Acetone cyanohydrins
- D. Butanone cyanohydrin
Explanation: When HCN is added to any carbonyl compound it produces an adduct which contain both-CN group and -OH group attached to one carbon, called…
Correct answer: Acetaldehyde cyanohydrin- A. CH3CH2CH2CH2COCH3
- B. CH3CH = CHCH2CH(OH)CH3
- C. CH3CH2CH2CH2CH(OH)CH3
- D. All of these
Explanation: NaBH4 can reduce > C=O group to > CH-OH group but cannot reduce > C=C;. So, in product >C = C< will remain intact.
Correct answer: CH3CH = CHCH2CH(OH)CH3- A. Formaldehyde
- B. Propanone
- C. Acetaldehyde
- D. All of these
Explanation: Reactivity order: Aldehyde> Ketone Small aldehyde>large aldehyde Small ketone>large ketone Unsymetrical ketone>symmetrical ketone…
Correct answer: Formaldehyde- A. H
- B. H-
- C. H+
- D. H2
Explanation: H-: This represents a hydride ion (H⁻), which is the active reducing species in sodium borohydride (NaBH₄).
Correct answer: H-- A. Methyl alcohol
- B. Isopropyl alcohol
- C. Ethyl alcohol
- D. Neopentyl alcohol
Explanation: Acetone is a 3-C ketone. On reduction, it will produce a 3-C secondary alcohol.
Correct answer: Isopropyl alcohol370. For which one of the following pairs of compounds can be distinguished by means of Tollen's tests.
- A. HCHO and CH3CHO
- B. CH3COCH3 and CH3COCH2CH3
- C. CH3CHO and CH3COCH3
- D. CH3COOH and CH3COCH3
Explanation: All the aliphatic aldehydes gives positive test (silver minor formation on the inner side of test tube) while ketones don't.
Correct answer: CH3CHO and CH3COCH3- A. CH3CH2CHO
- B. HCHO
- C. CH3CHO
- D. CH3COCH3
Explanation: Ketones are reluctant towards oxidation. Acetone is a ketone. Ketones are generally less susceptible to oxidation compared to aldehydes.
Correct answer: CH3COCH3- A. CuSO4 + NaOH + Citric acid
- B. AgNO3 + NH4OH
- C. CuSO4 + NaOH + Tartaric acid
- D. K2Cr2O7 + Conc. H2SO4
Explanation: A, B, C are weak oxidizing agent, so they can oxidize aldehydes only (due to high reactivity than ketone) but not ketones but the…
Correct answer: K2Cr2O7 + Conc. H2SO4- A. Ag
- B. Cuprix oxide
- C. Cuprous oxide
- D. Soduim carboxylate
Explanation: Fehling's solution is alkaline solution containing cupric tartarate ion.
Correct answer: Cuprous oxide- A. HCHO
- B. -CHO
- C. CH3CHO
- D. CH3COCH3
Explanation: Aliphatic aldehydes are reactive than aromatic aldehydes and ketones so, a small aliphatic aldehyde can reduce Tollen's reagent
Correct answer: HCHO- A. Acetophenone
- B. Benzaldehyde
- C. 2-Butcne, 2of
- D. 3-Methyl 2-pentanone
Explanation: 3-Methyl-2-pentartone gives 3-Methyl-2-pentanol on reduction with NaBH4'
Correct answer: 3-Methyl 2-pentanone- A. Sodium acetate
- B. Ammonium acetate
- C. No salt formed
- D. Silver chloride
Explanation: Ammonium acetate. Explanation: Ammonical silver nitrate is a reagent used to test for the presence of halides.
Correct answer: Ammonium acetate- A. HCHO
- B. CH3CHO
- C. CH3-CH2-CHO
- D. CH3CH2 -OH
Explanation: Aldehydes and small methyl ketones react with a saturated aqueous solution of sodium bisulphite to form a crystalline white precipitate of…
Correct answer: CH3CH2 -OH- A. α-C
- B. α-H
- C. Basic medium
- D. All of these
Explanation: Aldehydes and ketones possessing ɑ-hydrogen atoms react with a cold dilute solution of an alkali to form addition products known as aldols.
Correct answer: All of these- A. Methanol
- B. Ethanol
- C. Propanone
- D. 2-pentanone
Explanation: Aldehydes and ketones possessing α-hydrogen atoms react with a cold dilute solution of an alkali to form addition products known as…
Correct answer: Methanol- A. NaHSO3
- B. HCN
- C. NH2NH2
- D. Aldol
Explanation: This reaction is used for the separation and purification of carbonyl compounds from non-carbonyl compounds such as alcohols.
Correct answer: NaHSO3