Question

Is phenol more acidic than menthol?

Even thought both menthol and phenol both have OH group, phenol is more acidic. What is the cause of that?
Write structures of anions after losing H+ i explain trough resonance why phenol is more acidic.

Answer 1

The phenoxide anion is somewhat stablized by resonance.......

Explanation:

Menthol is `C_10H_19OH`, whose asymmetric synthesis (amongst other things) won Ryoji Noyori a Nobel Prize in 2001, an alicyclic (i.e. secondary) alcohol. The acidity of this alcohol would be much less than that of phenol, for which phenoxide anion can be produced in water using sodium hydroxide.

The phenoxide anion is resonance-stabilized, and the negative charge can be delocalized, i.e. distributed, around the 6 centres of the aromatic ring as well as the oxygen atom. This resonance stabilization, the delocalization of negative charge, contributes to the acidity of phenol. On the other hand, the anion of menthol is confined to the oxygen centre.

I know which smells nicer though, and it ain't the phenol........