A Chromatography column, packed with silica gel as stationary phase, was used to separate a mixture of compounds consisting of (a) benzanilide, (b) aniline and (c) acetophenone. When the column is eluted with a mixture of solvents, hexane; ethyl acetate(20:80), the sequence of obtained compounds is
- (A)(b), (c) and (a)
- (B)(a), (b) and (c)
- (C)(c), (a) and (b)✓ Correct
- (D)(b), (a) and (c)
Answer: (C)
Solution
On a silica column, which is a normal-phase, polar stationary phase, the least polar compound washes through first and the most polar is held back the longest. Acetophenone, with only a carbonyl, is the least polar; benzanilide, an amide, is intermediate; and aniline, which hydrogen-bonds strongly through its , is the most polar. The compounds therefore come off in the order acetophenone, then benzanilide, then aniline.
JEE Main · 2020 · 07 Jan 2020 · Shift 2 · Single correct option