Question

Out of o-nitrophenol and o-cresol which is more acidic?

Answer 1

The acidic character of alcohols is due to the polar nature of O - H bond. Higher the polarity of O - H bond, more will be the acidic strength. Due to – I and – R effect of nitro group, electron density decreases in the O - H bond of o-nitrophenol and thus polarity increases.

Whereas due to + I effect of — $C{H}_3$ group, electron density increases in the O - H bond of o-cresol. Thus, O - H bond of o-nitrophenol is weaker than O - H bond of o-cresol and o-nitrophenol is more acidic than o-cresol.