The acidic strength of glycolic acid and salicylic acid
is different from other acids, and the acidic strength of glycolic acid (Glycolic Acid) and salicylic acid (Salicylic Acid) is also discussed by everyone.

For glycolic acid, its structure contains carboxyl and hydroxyl groups, and the hydroxyl group is adjacent to the carboxyl group, which has a certain electronic effect. This hydroxyl group can use the induction effect to affect the carboxyl group. Due to its electronegativity, the electron cloud is slightly shifted to the hydroxyl group, which enhances the polarity of the hydrogen-oxygen bond in the carboxyl group, and hydrogen is more easily dissociated, so it becomes acidic.

For salicylic acid, in addition to the carboxyl group, there are still phenyl rings and phenolic hydroxyl groups. The benzene ring is a conjugated system and has a certain electron delocalization. The phenolic hydroxyl group forms p-π conjugation with the phenyl ring, which changes the density distribution of the electron cloud. At the same time, the carboxyl group also interacts with the phenyl ring. The conjugation effect of the phenolic hydroxyl group has a certain impact on the acidity of the carboxyl group. However, the electron-absorbing induction effect of the benzene ring weakens the electron cloud density of the carboxyl group to a certain extent, resulting in a different dissociation ability of carboxyl hydrogen.

Comparing the two, the acidity of glycolic acid is stronger than that of salicylic acid. The hydroxyl-induced effect of glycolic acid greatly assists the dissociation of carboxyl hydrogen. Although salicylic acid has a conjugated system, the conjugation effect of the phenolic hydroxyl group partially cancels the electron-absorbing induction effect of the phenyl ring, and the effect on the acidity of

Overall, glycolic acid is more acidic than salicylic acid, which is due to the difference in molecular structure and electronic effects between the two.