Question

For carbylamine reaction, we need hot alc. KOH and

• A. any primary amine and chloroform
• B. chloroform and silver powder
• C. a primary amine and an alkyl halide
• D. a mono alkyl amine and trichloromethane

Answer 1

The Correct Option is A

The Carbylamine reaction, also known as the Hofmann isocyanide synthesis, is a chemical reaction used to synthesize isocyanides (or carbylamines) from primary amines. The reaction involves the reaction of a primary amine with chloroform in the presence of a strong base like alcoholic potassium hydroxide (KOH).

Let's analyze the options given:

1. Any primary amine and chloroform: This is the correct combination for the Carbylamine reaction. In the presence of hot alcoholic KOH, a primary amine reacts with chloroform to form an isocyanide.
2. Chloroform and silver powder: This option lacks a primary amine, which is essential for the Carbylamine reaction. Hence, this is incorrect.
3. A primary amine and an alkyl halide: Alkyl halides are not involved in the Carbylamine reaction. Instead, chloroform is required. Thus, this is incorrect.
4. A mono alkyl amine and trichloromethane: While "trichloromethane" is another name for chloroform, the use of "mono alkyl amine" is not specific enough. However, the use of the term "any primary amine" is more accurate, making the first option correct.

Therefore, the correct option is 'any primary amine and chloroform', as it correctly specifies the necessary reactants for the Carbylamine reaction.

The chemical reaction can be represented as:

\text{R-NH}_2 + \text{CHCl}_3 + 3\text{KOH} \rightarrow \text{R-NC} + 3\text{KCl} + 3\text{H}_2\text{O}

Where \text{R-NH}_2 is the primary amine and \text{R-NC} is the isocyanide produced.

The reaction conditions of hot alcoholic KOH facilitate the formation of isocyanides, characterized by their distinctive, unpleasant smell.