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

Options

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

Answer

A

Explanation

`2H^(+) +2e rarr H_(2)(g)`
Applying Nernst Equation
`E_(H^(+)//H_(2)) = E_(H^(+)//H_(2))^(@) - (0.059)/(2)log.(pH_(2))/([H^(+)]^(2))`
`E_(H^(+)//H_(2)) = 0`
`:. E_(H^(+)//H_(2))^(@) = 0 - (0.059)/(2) log.(pH_(2))/([H^(+)]^(2))`
For the negative nature of `E_(H^(+)//H_(2))`