The density of water is higher than that of ice due to:

The intramolecular hydrogen bonding is present in

The number of $H_2O$ molecules participating in hydrogen bonding in $CuSO_4 \cdot 5H_2O$ is/are

$H_2O$ is a liquid while $H_2S$ is a gas due to:

Assertion $(A)$: Hydrogen fluoride has a higher boiling point than other hydrogen halides.
Reason $(R)$: Hydrogen fluoride exhibits strong hydrogen bonding. The correct option among the following is:

Water has high heat of vaporisation due to