Give the construction and working of a standard hydrogen electode with a neat diagram.

Explanation

To determine the potential of a single electrode experimentally, it is sombined with a stardard hydrogen electrode (electrode whose potential is known) and the EMF of the cell. So constructed is measured with a potentiometer. Standard hydrogen electrode is constructed and is used as standard electrode or reference electrode. Standard Hydrogen Electrode (SHE) or Normal Hydrogen Electrode (NHE).
Pure hydrogen gas is bubbled into a solution of 1M HCl along a platinum electrode coated with platinum block. A platinum block electrode placted in the solution at atmospheric pressure Generally the electrode is fitted into the tube. The tube will have two circular small holes. This tube is immersed in to acid solution such that one half of the circular hole is exposed to air and another half in the solution.
The following equalibrium exists at the electrode.
`1/2 H_(2(g))(1_(atm))hArrH_((aq))^(+)(1M) +e^(-)`