THE ANSWER CAN BE UNDERSTOOD EASILY BY LOOKING AT THE FOLLOWING POINTS:-
1. In case of alcohol the Oxygen atom is joined to the alkyl group on one side and hydrogen atom on the other side, being electron releasing in nature the alkyl group increase the electron density on Oxygen atom , thus making it less acidic.
2. +I effect: Positive inductive effect is shown by the electron releasing group makes the oxygen electron rich , making it difficult for oxygen to release H+ ion.
3. On the other hand in case of water there are hydrogens on the both sides of the Oxygen atom. As a result of this the Oxygen atom is able to release the H+ ion easily as shown below :-
H2O ———> H+ + OH–