…….X….. are crystalline, non-volatile and non- conducting in solid state. (X) Melts conduct electricity and on electrolysis liberate dihydrogen gas at anode. Here, X refers to

The ionic or saline hydrides are crystalline, non- volatile, and non-conducting in solid state. However, their melts conduct electricity and on electrolysis liberate dihydrogen gas at anode which confirms the existence of H ion. 2 Anode 2H melt H g 2e ->