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Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids MCQs | Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids Short Questions and Answers

(1) Polarisation of electrons in acrolein may be written as
[A]
[B]
[C]
[D]
Answer:
(2) Consider the following reaction;
CH3Br + Mg
compound C is:
[A] acetic acid
[B] acetaldehyde
[C] ethyl alcohol
[D] formic acid
Answer: ethyl alcohol
(3) The conversion of CH3OH to CH3COOH can be brought in by:

[A] K2Cr2O7/H+
[B] CO + Rh
[C] KMnO4
[D] H3PO4
Answer: CO + Rh
(4) Benzaldehyde and acetaldehyde can be distinguished by:
[A] iodoform test
[B] 2:4 DNP test
[C] NH3 reaction
[D] Wolff-Kishner's reduction
Answer: iodoform test
(5) Fehling's solution is:
[A] acidified copper sulphate solution
[B] ammoniacal cuprous chloride solution
[C] copper sulphate, Rochelle salt + NaOH
[D] none of the above
Answer: copper sulphate, Rochelle salt + NaOH
(6) Which compounds will not reduce Fehling's solution?
[A] Methanal
[B] Ethanal
[C] Trichloroethanal
[D] Benzaldehyde
Answer: Benzaldehyde
(7) Acetaldehyde normally reacts with
[A] only electrophiles
[B] only nucleophiles
[C] only free radicals
[D] both electrophiles and nucleophiles
Answer: only nucleophiles
(8) Muscone (an explosive perfume secreted by musk deer) has the structure

Its IUPAC name is:
[A] 3-methyl cyclopentadecanone
[B] methyl cyclopentadecan-3-one
[C] 3-methyl cyclotetradecanone
[D] 3-methyl cyclohexadecan-3-one
Answer: 3-methyl cyclopentadecanone
(9) Which of the following has most acidic hydrogen?
[A] 3-hexanone
[B] 2,4-hexanedione
[C] 2,5-hexanedione
[D] 2,3-hexanedione
Answer: 2,4-hexanedione
(10) Which can be reduced to corresponding hydrocarbon by Zn-Hg/conc HCl?
[A] Butan-2-one
[B] Acetic acid
[C] Acetamide
[D] Ethyl acetate
Answer: Butan-2-one
(11) Nucleophilic addition reaction will be most favoured in
[A]
[B] (CH3)2C=O
[C] CH3CH2CHO
[D] CH3CHO
Answer: CH3CHO
(12) The enolic form of acetone contains:
[A] 9 σ-bonds, 1π-bond and 2 lone pairs
[B] 8 σ-bonds, 2π-bonds and 2 lone pairs
[C] 10 σ-bonds, 1π-bond and 1 lone pair
[D] 9 σ-bonds, 2π-bonds and 1 lone pair
Answer: 9 σ-bonds, 1π-bond and 2 lone pairs
(13) In this reaction,

an asymmetric compound is generated. The acid obtained would be
[A] 50% D + 50% L-isomer
[B] 20% D + 80% L-isomer
[C] D-isomer
[D] L-isomer
Answer: 50% D + 50% L-isomer
(14) Ethane can be obtained from ethanal in one step by:
[A] Na-Hg + water
[B] Zn-Hg + conc.HCl
[C] aluminium isopropoxide and isopropyl alcohol
[D] LiAlH4 + ether
Answer: Zn-Hg + conc.HCl
(15) Which one of the following compounds on treatment with LiAlH4 will give a product that will give a positive iodoform test?
[A] CH3CH2CHO
[B] CH3CH2COOCH3
[C] CH3CH2OCH2CH3
[D] CH3COCH3
Answer: CH3COCH3
(16) Aldehydes and ketones will not form crystalline derivatives with
[A] sodium bisulphite
[B] phenyl hydrazine
[C] semicarbazide hydrochloride
[D] dihydrogen sodium phosphate
Answer: dihydrogen sodium phosphate
(17) Oxalic acid on treatment with conc. H2SO4 gives:
[A] CO + H2O2
[B] H2O +CO+CO2
[C] HCOOH + CO2
[D] HCOOH + CO2 +O2
Answer: H2O +CO+CO2
(18) Benzene sulphonic acid on treating with P2O5 gives:
[A] salicylic acid
[B] benzoic acid
[C] acid anhydride
[D] sodium benzoate
Answer: acid anhydride
(19) The IUPAC name of crotonaldehyde is:
[A] propenal
[B] but-2-en-l-al
[C] butan-2-en-l-al
[D] none of these
Answer: but-2-en-l-al
(20) The IUPAC name of the CH3COCH(CH3)2 is:
[A] 4-methyl isopropyl ketone
[B] 3-methyl-2-butanone
[C] isopropylmethyl ketone
[D] 2-methyl-3-butanone
Answer: 3-methyl-2-butanone

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