a. A solution of ferric chloride acidified with `HCl` is unaffacted when hydrogen is bubbled through it, but gets reduced when zinc is added to acidified solution. Explain.
b. When sodium hydride in fused state is electrolysed, hydrogen is discharged at the anode. Explain.

Explanation

(a) Molecular hydrogen is not so reactive as nascent hydrogen. Zinc reacts with the acid to produce nascent hydrogen which reduces ferric chloride into ferrous chloride.
(b) Sodium hydride, `NaH`, is an electrovalent compound in which dydrogen is present as an anion, `H^(ɵ)`. On electrolysis, it is discharged at anode.
`NaHharrNa^(o+)+H^(ɵ)`
At cathode: `Na^(+)+e^(ɵ)toNa`
At anode: `H^(ɵ)toH+e^(ɵ)`
`2HtoH_(2)uarr`