A galvanic cell is composed of two hydrogen electrods, one of which is a standard one. In which of the following solutions should the other electrode be immersed to get maximum e.m.f:

Options

A. 0.1 M HCl
B. `0.1 M H_(2) SO_(4)`
C. `0.1 M NH_(4)OH`
D. `0.01 MHCOOH`

Answer

C

Explanation

For given concentration cell ,
`E_(cell) = (RT)/(F) log ([H^(+)] _(R.H.S))/([H^(+)]_(L.H.S))`
for max. emf `[H^(+)]_(L.H.S)` should be min and that is for `NH_(4)OH` (aq).