Which of the following amines will undergo the Hofmann mustard oil reaction?

Solution

1. The Hofmann mustard oil reaction requires a primary amine to form a dithiocarbamic acid intermediate.
2. Primary aliphatic amines react with ${\text{CS}}_2$ to form $\text{R-NH-CSSH}$.
3. Subsequent treatment with ${\text{HgCl}}_2$ leads to the formation of alkyl isothiocyanate, $\text{R-N=C=S}$.
4. Aniline is an aromatic amine and does not yield the characteristic mustard oil smell under standard conditions.
5. Hence the answer is (B).