Question

bond length of C-O bond in phenol is shorter than that in methanol

Answer 1

we know that phenol having benzene ring with -OH attached. The oxygen atoms have lone pair which comes in the conjugation with benzene ring and hence, the C-O bond will attains a partial double bond character.
And we know that the methanol is aliphatic -OH compound and  the C-O bond having single bond character.
And the bond length of double bond is always shorter than the bond length of single bond, so phenol have shorter bond length than methanol.

Answer 2

Answer:

The oxygen atoms have lone pair which comes in the conjugation with benzene ring and hence, the C-O bond will attains a partial double bond character. ... And the bond length of double bond is always shorter than the bond length of single bond, so phenol have shorter bond length than methanol