Ethyl ethanoate is treated with NaOEt (1 mol) and then acidified to give A. A is treated with NaOEt followed by C2H5Br to give B. B is warmed with dilute NaOH, acidified and gently heated to give C. C is

JEE Advanced levelSingle correct optionDifficulty 3 of 3co095

Ethyl ethanoate is treated with NaOEt (1 mol) and then acidified to give A. A is treated with NaOEt followed by $C X_{2} H X_{5} Br$ to give B. B is warmed with dilute NaOH, acidified and gently heated to give C. C is

A is

CH X_{3} COCH X_{2} COOEt

. Alkylation at the doubly activated carbon gives B,

CH X_{3} COCH (C X_{2} H X_{5}) COOEt

. Dilute NaOH hydrolyses the ester, and the beta-keto acid loses

CO X_{2}

on heating. C is

CH X_{3} COCH X_{2} CH X_{2} CH X_{3}

, pentan-2-one.