The `emf` of given cell `Pt - underset(P_(1))(H_(2))|H^(+)|underset(P_(2))(H_(2) - Pt` is :

Options

A. `(RT)/(F)log.(P_(1))/(P_(2))`
B. `(RT)/(2F)"log e"(P_(1))/(P_(2))`
C. `(RT)/(F)"log e"(P_(2))/(P_(1))`
D. none of these

Answer

B

Explanation

`underset(p_(1))(H_(2))rarr2H^(+)+2e`
`2H^(+)+2erarrunderset(p_(2))(H_(2))`
`E_(cell)=E_(OP_(H))^(0)+E_(RP_(H))^(0)+(RT)/(2F)loge([P_(H_(2))]_(1))/([P_(H_(2))]_(2))`
`=(RT)/(2F)loge(P_(1))/(P_(2))`