If the pressure of H2 gas is increased from 1 atm to 100 atm. Keeping H+ concentration constant at 1 M, the voltage of hydrogen half cell at 25oC will be

H2(1 atm)→2H+(1 M)+2e−∴ EH2/H+=EH2/H+o−0.05912log⁡[H+]2PH2                   =0.00−0.05912log⁡(1)21=0.00 VNow, pressure is increased from 1 atm to 100 atm∴ EH2/H+=EH2/H+o−0.05912log⁡[H+]2PH2                  =0−0.05912log⁡(1)2100                  (  [H+]is constant )                  =−0.05912log⁡ 10−2=0.0591 V