Which of the following concentration cells with produce maximum `E_("cell")` at 298 K
[Take `P_(H_2)=1.0` atm in each case.]

Options

A. `Pt|H_2(g)|H^(+)(0.01M)||H^(+)(0.1 M) |H_2(g)|Pt`
B. `Pt|H_2(g)|NH_4Cl(0.01 M)||HCl (0.1 M) |H_2(g)|Pt`
C. `Pt|H_2(g)|H^(+)(0.1 M)||H^(+) (0.2 M) |H_2(g) | Pt`
D. `Pt|H_2(g)|H^(+)(pH=0.0)||H^(+)(pH=0.0)|H_2(g)|Pt`

Answer

B

Explanation

Since `(H^+)` given by `NH_4Cl` will be less than 0.01 M so cell emf will be more . `E_("cell")` increases as concentration of cathodic compartment increases.