Two isomers \( (A) \) and \( (B) \) with Molar mass \( 184 \, \mathrm{g/mol} \) and elemental composition \( \mathrm{C}, 52.2\% ; \mathrm{H}, 4.9\% \) and \( \mathrm{Br}, 42.9\% \) gave benzoic acid and \( p \)-bromobenzoic acid, respectively on oxidation with \( \mathrm{KMnO_4} \). Isomer \( 'A' \) is optically active and gives a pale yellow precipitate when warmed with alcoholic \( \mathrm{AgNO_3} \). Isomer \( 'A' \) and \( 'B' \) are, respectively.
