Which of the following will maximum pKa value?
Order of Acidity− o−nitrophenol> phenol> o−cresol> ethanol. o−nitrophenol is more acidic than phenol due to electron withdrawing nature of nitro group. o-crseol is less acidic than alcohol due to electron-releasing nature of methyl group. Phenoxide ion is resonance stabilized but ethoxide ion is not. Thus, phenol is more acidic than alcohol. Greater the pKavalue, less is the acidity.