JEE Main 26-Aug-2021 Shift 2 Solved Paper

(A) This reaction is reverse of esterification. As it takes place in presence of acid and the ester molecule gets hydrolysed, the reaction is called as acidic hydrolysis of ester (hydrolysis is breaking of molecule in presence of water). Acidic hydrolysis is reversible reacton, hence does not go to completion.

CH3COOC2H5

Ester

H2SO4

────▶

H2O

C2H5‌OH

Alchohol

(B) Diisobutylaluminium hydride (DIBAL-H) is a reducing agent, which reduces ester to aldehyde.

CH3COOH3

Ester

DIBAL−H

──────▶

H2O

CH3‌CHO

Aldehyde

(C) This reaction is called Stephen aldehyde synthesis which involves preparation of aldehyde from nitrile using SnCl2,HCl and quenching of resulting iminium salt
([R−CH=NH2]+Cl−)with H2O.

CH3C≡N

Nitrile

Sn‌Cl2

────▶

HCl∕H2O

CH3‌CHO

Aldehyde

(D) Grignard reagent (CH3‌MgBr) attack electrophilic carbon in the nitrile to form imine salt, this salt then gets hydrolysed to form a ketone. Thus, the correct match is (c) A → 2, B → 3, C → 4, D → 1.