State the factors affecting the strength of a hydrogen bond.

(N/A) The strength of a hydrogen bond is primarily affected by the following factors:
$1$. $\text{Electronegativity}$: The strength of the $H$-bond depends on the electronegativity of the atom bonded to the hydrogen atom. As the electronegativity of the atom decreases,the strength of the $H$-bond decreases.
$2$. $\text{Physical state}$: The strength of the $H$-bond is influenced by the intermolecular distance. In the solid state,the intermolecular distance is the smallest,leading to the strongest $H$-bonding,whereas in the gaseous state,the distance is the largest,leading to the weakest $H$-bonding.
For example,the strength of $H$-bonding in water follows the order:
$(H_2O_{(s)} \text{ (Ice)}) > (H_2O_{(l)} \text{ (Water)}) > (H_2O_{(g)} \text{ (Vapour)})$.