Arrange the following compounds in increasing order of acidity and give a suitable explanation. Phenol, o-nitrophenol, o-cresol
increasing order of the acidity of the given compounds: o-cresol < Phenol < o-nitrophenol.
The presence of an electron-withdrawing group (–NO2) at an ortho position with respect to the –OH group, enhances the acidic strength of the compound by stabilizing the phenoxide ion, whereas, the presence of electron releasing group (alkyl group) do not favour the formation of phenoxide ion. Thus, an electron releasing group decreases the acidic strength of the compound. Thus, o-nitrophenol is most acidic and o-cresol is the least acidic in nature among the three given compounds.