Question

Why do aqueous solutions of phenol give acidic solutions?

Answer 1

You've got phenol, `C_6H_5OH`.....?

Explanation:

Because the `"phenoxide anion"` is stabilized somewhat by resonance, and delocalization of charge density, `"phenol"`, and its derivatives are mildly acidic......

`C_6H_5OH(aq) + H_2O(l)rarrC_6H_5O^(-) +H_3O^+`

or since you specified an `"Arrhenius acid".........`

`C_6H_5OH(aq) stackrel(H_2O)rarrC_6H_5O^(-) +H^+`

`pK_a=8.00`

Substitution of the ring by nitro groups that cause the charge density of the anion to DECREASE, causes the acidity to increase. `"1,3,5-trinitrophenol"`, `1,3,5-(O_2N)_3C_6H_2OH` is otherwise known as `"picric acid"`, whose `pK_a=0.38`, very strong for a carbon acid.