Organic Chemistry Basic Principles and Techniques MCQs

 Organic Chemistry – Some Basic Principles and Techniques 1. Which is the best-suited method for the separation of para and ortho-nitropheno...

 Organic Chemistry – Some Basic Principles and Techniques

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)