a) Draw contributive forms of the mesomerism of phenol
!
b) Why is phenol a stronger acid than propan-2-ol ?
Due to mesomerism, phenol has a partial positive charge on the $O$ atom. This charge increases the polarity of the $OH$ and facilitates heterolytic cleavage of this bond and thus the departure of $H^+$. In the case of propan-2-ol, the effect exerted by the $I\;+$ of isopropyl weakens the polarity of the $OH$ and makes the departure of $H^+$ less easy:
c) Draw contributortive forms of the mesomerism of benzaldehyde!
d) Why phenol tends more to electrophilic substitutions than benzaldehyde?
In phenol, the aromatic ring is enriched in electrons due to its mesomerism, whereas in benzaldehyde the opposite is true.
