CBSE Class 12 Chemistry Aldehydes Ketons Carboxylic Acids Questions

Question: Carbonyl compounds are the constituents of
(a) fabrics
(b) flavouring
(c) plastics and drugs
(d) All of these

Answer: d

Question: The bond angle and structure of carbonyl compounds respectively are
(a) 120° and trigonal planar
(b) 109°28' and tetrahedral
(c) 120° and tetrahedral
(d) 109°28' and trigonal planar

Answer: a

Question: Which of the following substrates give the same product on the reduction with DIBAL-H?
(a) CH₃ — (CH₂)₉— CN and CH3(CH₂)₉ — COOH   
(b) CH₃ — (CH₂)₉— CN₃and CH3(CH₂)₉ — COOC₂H₅
(c) CH₃ — (CH₂)₉ — COOH and CH₃ (CH₂)₉ — CHO  
(d) CH₃ (CH₂)₉ —COOH and CH₃(CH₂)₉ COOC₂H₅

Answer: b

Question: The name of simplest aromatic aldehyde carrying the aldehyde group on a benzene ring is/are
(a) carbaldehyde
(b) benzene carbaldehyde
(c) benzaldehyde
(d) Both (b) and (c)

Answer: d

Question: The most suitable reagent for the conversion of R—CH₂—OH→R—CHO  is
(a) KMnO₄
(b) K₂Cr₂O₇
(c) H₂SO₄
(d) PCC (pyridinium chlorochromate)

Answer: d

Question: The compounds methanal, ethanal and propanone are miscible with water because they form
(a) van der Waals’ forces with water
(b) ‘H’-bonding with water
(c) dipole-dipole bond with water
(d) ion-dipole bond with water

Answer: b

Question: Name the product formed during the decarboxylation of malonic acid.
(a) Acetic acid
(b) Ethanone
(c) Propanone
(d) Formic acid

Answer: a

Question: Identify the example in which nucleophilic addition followed by elimination reaction occur respectively in the carbonyl compound.
(a) Addition of Grignard reagent
(b) Addition of sodium sulphide
(c) Addition of HCN
(d) Addition of NH₃

Answer: d

Question: Alcohol vapours are passed over which of the following catalysts to give aldehydes and ketones?
(a) S or Pd
(b) Ag or Cu
(c) F or Cl
(d) Li or K

Answer: b

Question: Which of the following compounds produces an orange-red precipitate with 2, 4-DNP reagent?
(a) Acetamide
(b) Dimethyl ether
(c) Butanone
(d) Propylbutanoate

Answer: c

Question: Some higher members of aliphatic carboxylic acids known as fatty acids occur in natural fats as esters of glycerol. How many C-atoms do they contain?
(a) C₁₂-C₁₈
(b) C₁₀-C₁₅
(c) C₅-C₁₀
(d) C₂₀-C₃₀

Answer: a

Question: Select the acid(s) which cannot be prepared by Grignard reagent?
(a) Acetic acid
(b) Succinic acid
(c) Formic acid
(d) All of these

Answer: a

Question: On heating an aldehyde with Fehling’s reagent, a reddish brown precipitate is obtained due to the formation of
(a) CuO
(b) Cu₂O 
(c) CuSO₄
(d) Cu²⁺+O⁻H

Answer: b

Question: Carboxylic acids have higher boiling points than aldehydes, ketones and even alcohols of comparable molecular mass. It is due to
(a) more extensive association of carboxylic acid via van der Waals’ force of attraction
(b) formation of carboxylate ion
(c) formation of intramolecular H-bonding
(d) formation of intermolecular H-bonding

Answer: d 

Question:  Which of the following reagents is/are used for the conversion of ethanoic acid to ethanoic anhydride?
(a) SOCl₂,Δ
(b) PCl₃,Δ
(c) P₂O₅,Δ
(d) All of these

Answer: c

Question: Diborane easily reduce the functional group such as
(a) acid
(b) ester
(c) nitro
(d) halo

Answer: a

Question: What is the common name of 2-methylpropanoic acid?
(a) Adipic acid
(b) Crotonic acid
(c) Isobutyric acid
(d) Acrylic acid

Answer: c

Question: Aromatic carboxylic acids do not undergo Friedel-Crafts reaction because
(a) carboxyl group acts as an activating and meta-directing group
(b) carboxyl group act as a deactivating and ortho and para directing group
(c) carboxyl group act as an activating and ortho-directing group
(d) carboxyl group acts as deactivating and the catalyst

Answer: b

Question: Which of the following acid is used in rubber, textile, dyeing, leather and electroplating industries?
(a) Hexanedioic acid
(b) Ethanoic acid
(c) Methanoic acid
(d) Sodium benzoate

Answer: c