What evidence that you can give to say that oxygen atom in phenol is `sp^2` hybridised. 

Carbon atom in carbene is in sp^(2) hybridisation

(A) In methanol C-O bond length is 1.42Å, but in phenol, it is 1.36Å. (R) In methanol carbon atom is sp^3 hybridised and in phenol, carbon atom bearing the hydroxyl group is sp^2 hybridised.

Phenols are more acidic than alcohols due to (a) In phenols,- OH is attached to sp^(2) hybridised carbon but in alcohols , -OH is attached to sp^(3) hybridised carbon (b) Phenoxide ion is more stable than alkoxide due to resonance (c) Phenoxide ion is more stable than phenol

The negatively charged carbon atom in the carbanion is in sp^(3) hybridisation. Its shape is pyramidal or tetrahedral with one lone pair

How can you say that mouth is a munching machine ?

What is the valency of oxygen that you can calculate by the method discussed above?

(A) : Acetylene reacts with ammonical cuprous chloride to form red precipitate (R ) : Hydrogen atom bonded to sp hybridised carbon atom is acidic in nature.