What happens when ionic hydrides of s-block elements in molten state are electrolysed?

Options

A. Hydride ion migrates at cathode
B. Dihydrogen is liberated at cathode
C. Hydride ion reforms metal hydride
D. Dihydrogen is liberated at anode

Answer

D

Explanation

When ionic hydrides of s-block elements are subjected to electrolysis, dihydrogen gas is liberated at anode which confirms the existence of hydrogen in the form of hydride ion `(H^(-))`. Following reactions takes place:
`MH(l)hArrM^(+)(aq)+H^(-)(aq)`
At cathode
`M^(+)(aq)+e^(-)toM(s)`
At anode
`2H^(-)(aq)-2e^(-)to2H(g)`
`H+HtoH_(2)(g)`