MCQs on Organic Chemistry

MCQs on Organic Chemistry

1. Which is the best-suited method for the separation of para and ortho-nitrophenols from 1:1 mixture?

(a) crystallisation

(b) chromatography

(c) sublimation

(d) steam distillation

Answer: (d)

2. Find the incorrect statement for a nucleophile

(a) A nucleophile is a Lewis acid

(b) Nucleophiles do not seek electron

(c) Ammonia is a nucleophile

(d) Nucleophiles attack low electron density sites

Answer: (a)

3. Which among the following is the most deactivating meta-directing group in aromatic substitution reaction?

(a) -COOH

(b) -SO₃H

(c) -NO₂

(d) -CN

Answer: (c)

4. Ammonia evolved from 0.75 g of the soil sample in the Kjeldahl’s method for nitrogen estimation, neutralises 10 ml of 1M H₂SO₄. Find the percentage of nitrogen present in the soil

(a) 35.33

(b) 37.33

(c) 43.33

(d) 45.33

Answer: (b)

5. The correct order of increasing nucleophilicity is

(a) Cl^– < Br^– < I^–

(b) Br^– < Cl^– < I^–

(c) I^– < Br^– < Cl^–

(d) I^– < Cl^– < Br^–

Answer: (a)

6. Homologous series of alkanols have a general formula

(a) C_nH_2nO₂

(b) C_nH_2nO

(c) C_nH_2n+1O

(d) C_nH_2n+2O

Answer: (d)

7. Find the compound which undergoes nucleophilic substitution reaction exclusively by an SN1 mechanism

(a) Benzyl chloride

(b) Chlorobenzene

(c) Ethyl chloride

(d) Isopropyl chloride

Answer: (a)

8. Which of the following methods is best suited for the separation of a mixture containing naphthalene and benzoic acid

(a) Crystallisation

(b) Chromatography

(c) Sublimation

(d) Distillation

Answer: (c)

9. How many structural isomers are possible if one hydrogen in diphenylmethane is replaced by chlorine?

(a) 8

(b) 4

(c) 7

(d) 6

Answer: (b)

10. Why do we boil the extract with conc. HNO₃ in Lassaigne’s test for halogens?

(a) to increase the concentration of NO₃^– ions

(b) to increase the solubility product of AgCl

(c) it increases the precipitation of AgCl

(d) for the decomposition of Na₂S and NaCN formed

Answer: (d)