Question

Why p- benzoquinone doesn't show tautomerism?
And also tell if o-benzoquinone can show tautomerism or not.

Answer 1

Quinone has an α-hydrogen, however, its a vinylic hydrogen(hydrogen attached to a carbon atom which is sp2 hybridized), its very difficult to abstact such a hydrogen, and hence it becomes very less acidic. Therefore, no abstraction of α-hydrogen from it, by a base, hence, it does not show tautomerism! Same reason is applicable for o benzoquinone. It also does not show tautomerism.