The tertiary aromatic amine shown is treated with cold NaNO2/HCl. Which structure is the product (green solid as its hydrochloride)?

JEE Main levelSingle correct optionDifficulty 2 of 3nc256

The tertiary aromatic amine shown is treated with cold $NaNO X_{2}$ / $HCl$ . Which structure is the product (green solid as its hydrochloride)?

The compound shown is N,N-dimethylaniline. Nitrous acid generates the nitrosonium ion

NO X^{+}

, which attacks the strongly activated ring (no N-H is available for nitrosation) at the para position, giving N,N-dimethyl-4-nitrosoaniline.