A half-cell called standard hydrogen electrode
represented by Pt(s)l H2(g)lH+(aq), is assigned
a zero potential at all temperatures corresponding to the reaction;
H+ (aq) + e- ---->1/2H2(g)
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.
= 1.05 V – 0.0295 x log 80
= 1.05 V – 0.0295 x 1.9031
= 1.05 V – 0.056 = 0.99 V.