Both Na and H occur in group 1 of the periodic table ,yet melting point of HCI is `-114^(@)C.` Why ?

Explanation

Though Na and H are present in the group 1, they differ in their electronegativities. The electronagativity of H is 2.1 and that of Na is 039. Due to large electronegativity difference between Na and Cl(3.0 - 0.9 = 2.1), NaCl is ionic in nature and exists as a crystalline solid with very high melting point `(800^@C)`. On the other hand, HCl is polar covalent due to small
electronegativily differnce (3.0 - 0.9 = 2.1) and exists in the gaseous state at room temperature. In order to solidify it, a very low temperature `(-114^@C)` is needed. s needed.