JEE Main 2026 Apr 6 Shift 1, Chemistry Q17: Carboxylic Acid Derivatives

tert-Butanol has no $\alpha$-hydrogen with respect to the -OH bearing carbon's neighbours that could be dehydrogenated; with Cu at $573$ K it instead undergoes dehydration to give isobutylene (2-methylpropene), $({\text{CH}}_3{)}_2{\text{C=CH}}_2$.

Step (ii): acid-catalysed addition of benzoic acid across the alkene follows Markovnikov's rule. The proton adds to the less substituted carbon, generating the tertiary carbocation $({\text{CH}}_3{)}_3{\text{C}}^{+}$, which is trapped by the carboxylate oxygen of PhCOOH.

Net result: tert-butyl benzoate, ${\text{Ph-C(=O)-O-C(CH}}_3{)}_3$.

$\therefore P$ corresponds to option (3).