Question

What will be the Product (C) and (D) :

A.

B.

C.

D.

Answer 1

When aniline and alkyl halide react, a substitution reaction occurs and the halide ion is replaced. When a quaternary ammonium salt reacts with aq. KOH, the elimination reaction of quaternary ammonium salt is termed as the Hofmann Eliminations.

Complete step by step answer:
Aniline is nucleophilic and alkyl halide is electrophilic in nature. When both of these react, a substitution reaction occurs and the halide ion is replaced. With excess of alkyl halide, quaternary ammonium salt formation occurs.
With excess methyl iodide, in the presence of $N{a_2}C{O_3}$ solution, N, N-dimethylaniline produces N, N, N-trimethylanilinium Iodide

The nitrogen atom of primary amines contains a lone pair of electrons. So, primary amines are strongly nucleophilic in nature. Moreover, the hydrogen atoms on nitrogen are easily replaceable. So, primary amines can act as nucleophiles and can react with alkyl halides. In the presence of excess alkyl halides, one amine molecule can repeatedly react with a number of alkyl halide molecules and result in the formation of a quaternary ammonium salt.
When a quaternary ammonium salt reacts with aq. KOH, the elimination reaction of quaternary ammonium salt is termed as the Hofmann Eliminations. The counter anion of quaternary ammonium salt is often replaced by the more basic hydroxide ion through reaction with KOH (potassium hydroxide). The resulting hydroxide salt must be then heated to effect the E2 like elimination of a three-degree amine.

Therefore, the correct answer is option (B).

Note: The less stable trans-cyclohexane is the chief product accompanied by the sis-isomer. An anti E2 transition state would necessarily give the cis-cycloalkane, so the trans isomer must be generated by a syn-elimination.