Sodium reacts with dihydrogen to form a crystalline ionic solid. It is non-volatile and a non-conductor of electricity. It also reacts vigorously with water to liberate `H_(2)` gas. Write the formula of the ionic solid and give reaction between this solid & water. What happens when the ionic solid in its molten state is electrolysed?

Explanation

Sodium reacts with dihydrogen to form sodium hydride which is a crystalline ionic solid.
2 Na + `H_(2) underset(" "rarr) Delta 2"Na"^(+)H^(-)`
Sodium hydride reacts with water as follows-
2NaH + 2`H_(2)O " " rarr 2"NaOH" + 2H_(2)`
Sodium hydride, in its solid state does not undergo electro-lysis. However, in its molten state, undergo electrolysis. However, in its molten state, NaH undergoes electrolysis to liberate dihydrogen `(H_(2))` at anode and metallic sodium at cathode.
`Na^(+)H^(-)("molten")underset(rarr)" Electrolysis "2Na("molten")^(+)H_(2)`(g)
`" ""Cathode" " "" anode"`