The reduction potential of hydrogen half cell will be negative if :

Options

A. `p(H_(2)) = 2` atm and `[H^(+)] = 1.0` M
B. `p(H_(2)) = 2` atm and `[H^(+)] = 2.0` M
C. `p(H_(2)) = 1` atm and `[H^(+)] = 2.0` M
D. `p(H_(2)) = 1` atm and `[H^(+)] = 1.0` M

Answer

A

Explanation

Pt `|H_(2) (g) |H^(+) (aq)`
`H^(+) + e^- to 1/2 H_(2) (g)`
`E = E^(@) - (0.059)/(1) "log" (p(H_(2))^(1/2))/([H^(+)])`
` E = E^(@) - (0.059)/(1) "log" ((2)^(1/2))/(1) = -`ve .