Why has phenol smaller dipole moment than methanol ?

Explanation

`CH_(3)` group is electron releasing group and therefore, it increases the negative charge on the oxygen atom in `CH_(3)COH`. Therefore, C-O bond in it is more polar and hence methanol has high dipole moment. Phenyl group is electron attracting group and it reduces negative charge on the oxygen in `C_(6)H_(5)OH`. As a result, C-Obond is less polar in phenol and therefore, phenol has small dipole moment.