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

Explanation

Through Na and H are present in the group 1, they differ in their electronegativities. The electronegativity of H is 2.1 and that of Na is 0.9 Dut 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 covale due to small electronegativity difference (3.0-2.1=0.9) and exists in the gaseous state at room temperature. order to sokidify it, a very low temperature `(-114^(@)C)` in needed.