An electron-withdrawing group is a nitro – group. The electron density in the O – H bond is reduced by the presence of this group in the ortho position. As a result, it is simpler to give away a proton. Furthermore, resonance stabilizes the o-nitrophenoxide ion produced when protons are lost. As a result, ortho nitrophenol is a more powerful acid. A methoxy group, on the other hand, is an electron-releasing group. As a result, the electron density in the O – H bond increases, making proton loss difficult. As a result, ortho–nitrophenol is acidic in comparison to ortho–methoxyphenol.