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-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) CnH2nO2
  • (b) CnH2nO
  • (c) CnH2n+1O
  • (d) CnH2n+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 NO3ions
  • (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)

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