# Why is p-methoxyphenol less acidic than phenol?

They have slightly different $$\mathrm{p}K_\mathrm{a}$$ values of 9.9 (phenol) vs 10.2 (p-methoxyphenol). They both have the same number of resonance structures too.

My guess is that the resonance structure for p-methoxyphenol with the lone pair on the para carbon contributes less to the stabilisation of the negative charge since it's in an electron rich area (near the lone pairs of the methoxy group oxygen).

Is this a valid explanation? If not, what is the true reason?

• – Mithoron Aug 2 '19 at 22:42