Write a note on standard hydrogen electrode.

Explanation

According to the convention , a half -cell called standard hydrogen electrode, represented by `Pt_((s)) | H_(2(g)) |H_((g))^+` , is assigned a zero potential at all temperatures corresponding to the reaction.
Construction of hydrogen electrode.
The standard hdyrogen electrode consists of a plantinum electrode coated with platinum black. The electrode is dipped in an acidic solution and pure hydrogen gas is bubbled through it .
The concentration of both the reduced and oxidised forms of hydrogen is maintained at unity.
`1/2 H_(2(g)) to H_((aq))^+ + e^- `.....(oxidation)
`H_((aq))^+ + e^- to 1/2 H_(2(g)) `.....(Reduction)
This implies that the pressure of hydrogen gas is one bar and hte concentration of hydrogen ion in the solution is one molar.
Uses : Half cell electrode potential of any cell can be measured by taking standard hydrogen electrode as a reference electrode . At 298 K temperature , the cell potential obtained for the galvanic cell constructed with the help of standard hydrogen electrode with another electrode , then the potential obtained is the potential of that half-cell.