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

Options

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

Answer

B

Explanation

`2H^(+)+2e^(-)rarrH_(2)`
`E_(2H^(+)//H_(2))=E_(2H^(+)//H_(2))^(@)-(0.059)/(2)"log"(p(H_(2)))/([H^(+)]^(2))`
`E_(2H^(+)//H_(2))` will be negative if `p(H_(2))gt[H^(+)]^(2)`
i.e., `p(H_(2))=2` atm and `[H^(+)]=1`M.