$ a $ is phenol, sometimes called carbolic "acid".
$ b $ is picric acid, a powerful explosive accidentally found by Eugène Turpin.
1) Where does the strong acidic character of these substances come from?
2) What is the strongest acid?
1) The $-M$ effect of the benzene ring attracts a doublet of oxygen from $OH$ group. This becomes more positive, the electron density between $O$ and $H$ is diminished, which facilitates the departure of $H^+$
2) $-NO_2$ groups attract electrons out of the benzene ring and induce positive charges in their meta-positions, and therefore on the carbon carrying the $OH$ group, which increases furthermore the effect mentioned in 1)
$ a $ is phenol, sometimes called carbolic "acid".
$ b $ is picric acid, a powerful explosive accidentally found by Eugène Turpin.
1) Where does the strong acidic character of these substances come from?
2) What is the strongest acid?
