Describe the construction and working of standard hydrogen electrode. 

Explanation

The standard hydrogen electrode consists of a platinum electrode coated with platinum black. The electrode is dipped in an acidic solution containing `1M H^(+)` ions. Pure hydrogen gas at one bar pressure is bubbled through it.
Standard hydrogen electrode (SHE) is represented as
`(Pt(s)|H_(2)(g)|H^(+)(aq)`
Potential is developed when equillibrium attained between `H^(+)` ions of the solution and `H_(2)` gas on the interface of the electrode.
`H^(+)(aq)+e^(-) to 1/2 H_(2)(g)`
The electrode potential for standard hydrogen electrode (SHE) is taken zero at all temperature.