JEE Main 2021 · 17 March · morning · Single correct · +4 / −1

Which of the following reaction is an example of ammonolysis?

  1. (a) C₆H₅COCl + C₆H₅NH₂ → C₆H₅CONHC₆H₅
  2. (b) C₆H₅CH₂CN →([H]) C₆H₅CH₂CH₂NH₂
  3. (c) C₆H₅CH₂CN →(HCl) C₆H₅N +H₃Cl⁻
  4. (d) C₆H₅CH₂Cl + NH₃ → C₆H₅CH₂NH₂
Answer and solution

Answer (d) C₆H₅CH₂Cl + NH₃ → C₆H₅CH₂NH₂

Solution

Chemistry ma’am · 2 steps

Ammonolysis means ammonia itself breaks a C–X bond, so first look for NH₃ among the reactants.

  1. What ammonolysis is. In ammonolysis, ammonia acts as the nucleophile and attacks an alkyl or benzyl halide. The halogen leaves and an amine forms. The word itself means splitting a bond with ammonia.

    C₆H₅CH₂Cl + NH₃ → C₆H₅CH₂NH₂ + HCl

    OptionWhat attacks the substrateType of reaction
    (a)Aniline, C₆H₅NH₂Acylation (benzoylation) of aniline, giving an amide
    (b)Hydrogen, [H]Reduction of a nitrile to a primary amine
    (c)HClAcid–base salt formation
    (d)Ammonia, NH₃Substitution of Cl by NH₂: ammonolysis
  2. So. Only (d) uses ammonia to cleave the C–Cl bond of benzyl chloride and give benzylamine. The answer is (d).

The idea to keep. Ammonolysis is ammonia acting as the nucleophile on an alkyl or benzyl halide. If NH₃ is not the reagent, it is not ammonolysis, however amine-like the product looks.

Answer from the NTA final answer key. Solution by PrepWiser.

Study Amines & Diazonium Salts

Asked about 170 times in JEE Main since 2020. This question is from 2021.