Question

calculate the ratio of p character in the carbon atom which is attached directly to OH in allylic ,vinylic and benzylic alcohol respectively?

Answer 1

In vinylic alcohols, the carbon attached to alcoholic group is sp² hybridized. One s and 2 p orbitals are involved in hybridization and hence the contribution of p orbital is 2/3 or 67%.
In Allylic and benzylic alcohols, the alcoholic group is attached to sp³ hybridized carbon. One s and 3 p orbitals are involved in the hybridisation process and hence the p character is ¾ or 75%.