Write a note on the standard hydrogen electrode $(SHE)$.

(N/A) According to the convention,a half-cell called the standard hydrogen electrode $(SHE)$,represented by $Pt_{(s)} | H_{2_{(g)}} (1 \ bar) | H^{+}_{(aq)} (1 \ M)$,is assigned a zero potential at all temperatures.
Construction of hydrogen electrode:
The standard hydrogen electrode consists of a platinum electrode coated with platinum black. The electrode is dipped in an acidic solution,and pure hydrogen gas is bubbled through it at $1 \ bar$ pressure.
The concentration of hydrogen ions in the solution is maintained at $1 \ M$.
The half-cell reactions are:
Oxidation: $\frac{1}{2} H_{2_{(g)}} \longrightarrow H^{+}_{(aq)} + e^{-}$
Reduction: $H^{+}_{(aq)} + e^{-} \longrightarrow \frac{1}{2} H_{2_{(g)}}$
Uses:
The standard hydrogen electrode is used as a reference electrode to measure the electrode potential of any other half-cell. By constructing a galvanic cell with the $SHE$ and another electrode,the measured cell potential at $298 \ K$ directly gives the potential of that half-cell,as the potential of the $SHE$ is taken as zero.