At what pH of HCl solution, will hydrogen gas electrode show electrode potential of -0.118 V ? `H_(2)` gas is bubbled at 298 K and 1 atm pressure.

Explanation

Writing electrode reaction as reduction reaction, `H^(+)+e^(-)to(1)/(2)H_(2)`
Applying nernst equation, `E_(H^(+)//H_(2))=E_(H^(+)//H_(2))^(@)-(0.0591)/(1)"log"(1)/([H^(+)])=0+0.0591log[H^(+)]`
or `-0.118=-0.0591pH` or `pH=2` (`becausepH=-log[H^(+)])`