Which one of the following compounds will readily react with dilute NaOH ?
- C6H5CH2OH
- C2H5OH
- C6H5OH
- (CH3)3COH
Answer
(3) C6H5OH
Solution
C6H5OH + NaOH C6H5O-Na+ + H2O
Because the phenoxide ion is resonance-stabilised, phenol (pKa ≈ 10) is a stronger acid than water and reacts readily with dilute NaOH.
(A), (B), (D) are alcohols (pKa ≈ 16–18), weaker acids than water, so they do not react.
Answer: (3)