Question

Which of the following is most acidic?
(a) Benzyl alcohol
(b) Cyclohexanol
(c) Phenol
(d) m - chlorophenol

Answer 1

Alpha carbon of benzyl alcohol and cyclohexanol is $s{p}^3$ hybridised while in phenol and m-chlorophenol, it is $s{p}^2$ hybridised. In m-chlorophenol electron withdrawing group (— CI) is present at meta position.
Presence of electron withdrawing group increases the acidic strength. So, m-chlorophenol is most acidic among all the given compounds. The correct option is (d).