Question

Give reasons of the following.
(i) Phenol is more acidic than methanol.
(ii) The C-O-H bond angle in alcohols is slightly less than the tetrahedral angle $\left({109}^{\circ }{28}^{{}^{\prime }}\right)$.
(iii) $(C{H}_3{)}_{3}C-O-C{H}_3$ on reaction with HI gives $(C{H}_3{)}_{3}C-IandC{H}_3-OH$ as the main products and not $(C{H}_3{)}_{3}C-OHandC{H}_3-I$.

Answer 1

(1) Phenoxide ion is more stabilized than $-C{H}_{3}O$ ion through resonance. Thus, phenol is more acidic than methanol.

(2) Due to extensive intermolecular H-bonding the $-C-O-H$ bond angle in alcohol slightly less than tetrahedral angle. H-bond thrust the angle slightly.

(3) Since, $(CH{)}_3{C}^{+}$ is more stabilized through +I effect of three methyl group thus $(C{H}_3{)}_{3}C-I$ and $C{H}_{3}OH$ formed on treatment of $HI$ with $-(C{H}_3{)}_3-CO-C{H}_3$.

$MeC-O-Me\to M{e}_3{C}^{+}+Me{O}^{-}+HI\to M{e}_{3}C-I+MeOH$