The difference in reversible potential between oxygen reduction reaction and hydrogen evolution reaction of any pH in an aqueous electrolyte is . . . . . . . . volt.
[Given, standard reduction potentials for hydrogen evolution reaction, $$\frac{{{E^ \circ }2{H^ + }}}{{{H_2}}} = OV,SHE$$     and oxygen reduction reaction : $$\frac{{{E^ \circ }{O_2}}}{{4OH}} = 0.4V,SHE.$$     Also PH₂ = PO₂ = 1 atm]