Resonance structures of ortho nitro phenol:
Thus, presence of nitro group at ortho and para position increase the acidic character.
(HCl—ZnCl2) is lucas reagent, lucas reagent react with alcohol however it does not react with primary alcohol but readily gives turbidity with tertiary alcohols.
a) Reaction with (HCl—ZnCl2):
Butan-1-ol is primary alcohol thus no reaction occur.
where as 2-methyl butan-2-ol is tertiary alcohol, it forms 2-chloro-2-methylbutane.