A compound 'X' is acidic and it is soluble in NaOH solution, but insoluble in NaHCO₃ solution. Compound 'X' also gives violet colour with neutral FeCl₃ solution. The compound 'X' is :

Solution

Chemistry ma’am · 4 steps

Three clues, one answer: NaOH yes, NaHCO3 no, violet with FeCl3 means an OH sitting right on a benzene ring.

1. Read the options. (a) is cyclohexanol, (b) is phenol, (c) is benzyl alcohol, C₆H₅CH₂OH, and (d) is cyclohexylmethanol. All four have an -OH group, but only in (b) is it bonded directly to the ring carbon of a benzene ring.
2. Acid strength test. NaOH dissolves any acid stronger than water, but NaHCO₃ dissolves only acids stronger than carbonic acid, such as carboxylic acids. So 'X' is a weak acid: stronger than water, weaker than H₂CO₃.

   Compound	Soluble in NaOH	Soluble in NaHCO₃	Violet with neutral FeCl₃
   (a) cyclohexanol	no	no	no
   (b) phenol	yes	no	yes
   (c) benzyl alcohol	no	no	no
   (d) cyclohexylmethanol	no	no	no

3. Why phenol. In phenol the negative charge of the phenoxide ion spreads into the ring by resonance, so phenol (pKₐ ≈ 10) is acidic enough to react with NaOH but not with NaHCO₃. The -OH on the aromatic ring also forms a violet complex with Fe³⁺.
4. So. Every clue fits only phenol, so 'X' is option (b).

The idea to keep. Soluble in NaOH but not in NaHCO3 means a phenol, not a carboxylic acid. A violet colour with neutral FeCl3 confirms an OH bonded directly to an aromatic ring.

Answer from the NTA final answer key. Solution by PrepWiser.