4-Nitrotoluene is reduced with Sn/HCl to give A. A is treated with NaNO2/HCl at 273 K to give B. B is warmed with CuBr/HBr to give C, and C is heated with alkaline KMnO4 and acidified to give D. D is

JEE Advanced levelSingle correct optionDifficulty 3 of 3si141

4-Nitrotoluene is reduced with $Sn / HCl$ to give A. A is treated with $NaNO X_{2} / HCl$ at $273 K$ to give B. B is warmed with $CuBr / HBr$ to give C, and C is heated with alkaline $KMnO X_{4}$ and acidified to give D. D is

A is 4-methylaniline, B the 4-methylbenzenediazonium salt and C 4-bromotoluene (Sandmeyer). Alkaline

KMnO X_{4}

oxidises the methyl group fully to

- COOH

and the bromine and the positions are retained, giving 4-bromobenzoic acid.