Question

A solution of m-chloronailimne, m-chlorophenol and m-chlorobenzoic acid in ethyal acetate was extracted initially with a saturated solution of NaHCO₃ to give fraction A. The left over organic phase was extracted with dilute NaoH solution tio give fraction B. The final organiic layer was labelled as fraction C. Fractions A,B and C, contain respectively :

• A. m-chlorobenzoic acid, m-chloroaniline and m-chlorophenol.
• B. m-chlorobenzoic acid, m-chlorophenol and m-chloroaniline.
• C. m-chlorophenol, m-chlorobenzoic acid and m-chloronailine.
• D. m-chloroaniline m-chlorobenzoic acid and m-chlorophenol.

Hint:

Use differences in acidity: carboxylic acid reacts with NaHCO₃, phenol only with NaOH, and the weakly basic aniline stays in the organic layer.

Answer 1

The Correct Option is B

Step 1: Order of acidity: carboxylic acid (RCOOH) \(\gt\) H₂CO₃ \(\gt\) phenol \(\gt\) aniline (no acidic behaviour).
Step 2: NaHCO₃ (conjugate base of H₂CO₃) can deprotonate only acids stronger than carbonic acid: the benzoic acid. NaOH then deprotonates the phenol. The aniline is left behind.
Step 3: Therefore A = acid, B = phenol, C = amine.
Answer: Option 2 (B)