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NEET Chemistry · Organic Compounds Containing Nitrogen

Diazonium salts

Taught in NCERT Class 12 Chemistry, Chapter 9: Amines.

3 verified questions: Easy 0 · Medium 2 · NEET level 1

Sample questions

Sample 1Medium

A reaction scheme reads: aniline → (NaNO2 + HCl, 273–278 K) → A → (CuCN/KCN) → B. What are A and B?

  1. A

    A is benzenediazonium chloride and B is chlorobenzene

  2. B

    A is benzenediazonium chloride and B is benzylamine

  3. C

    A is benzenediazonium chloride and B is benzonitrile

  4. D

    A is phenol and B is benzonitrile

Show the answer
The answer is C.

Aniline is diazotised by nitrous acid at 273–278 K to give benzenediazonium chloride. With CuCN/KCN (Sandmeyer reaction) the diazonium group is replaced by –CN, giving benzonitrile.

  • A.

    Chlorobenzene is formed with CuCl/HCl; CuCN/KCN introduces a –CN group.

  • B.

    Benzylamine (C6H5CH2NH2) is the reduction product of benzonitrile, not the Sandmeyer product.

  • D.

    At 273–278 K aniline is diazotised; phenol would form only if the diazonium salt were warmed with water.

NCERT: Class 12 Chemistry, Chapter 9

Sample 2NEET level

Match the reagent in List I, each treated with benzenediazonium chloride, with the main organic product in List II. List I: A. Cu2Cl2/HCl B. KI C. H3PO2 and water D. Water, warmed List II: I. Benzene II. Iodobenzene III. Phenol IV. Chlorobenzene

  1. A

    A-IV, B-II, C-I, D-III

  2. B

    A-IV, B-II, C-III, D-I

  3. C

    A-II, B-IV, C-I, D-III

  4. D

    A-I, B-II, C-IV, D-III

Show the answer
The answer is A.

Cu2Cl2/HCl (Sandmeyer reaction) replaces the diazonium group by Cl, and KI replaces it by I. Hypophosphorous acid reduces the diazonium salt to benzene, and warming its aqueous solution hydrolyses it to phenol.

  • B.

    Swaps the products of H3PO2 (benzene) and warm water (phenol).

  • C.

    Swaps the products of Cu2Cl2/HCl and KI.

  • D.

    Swaps the products of Cu2Cl2/HCl and H3PO2.

NCERT: Class 12 Chemistry, Unit 9 (Amines), Chemical Reactions of Diazonium Salts

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