Which among the following has the highest melting point?
Which among the following has the highest melting point?
Phenol
p-Nitrophenol
p-Cresol
o-Nitrophenol
Solution
Due to intramolecular hydrogen bonding in ortho-isomer, the molecule remains in isolated state and it has a lower melting point.
In p-Cresol, non polar $-\mathrm{CH}_3$ group is present which does not participate in H -bonding. Due to effective intermolecular hydrogen bonding para-isomer remains in associated state and so p -nitrophenol has highest melting point.
