Question

What will be the emf for the given cell?
$Pt |H_{2}\left(g, P_{1}\right) | H^{+}_{(aq)} || H_{2}\left(g, P_{2}\right) | Pt$

• A. $\frac{RT}{F}$ In $\frac{P_{1}}{P_{2}}$
• B. $\frac{RT}{2F}$ In $\frac{P_{1}}{P_{2}}$
• C. $\frac{RT}{F}$ In $\frac{P_{2}}{P_{1}}$
• D. $\frac{RT}{2F}$ In $\frac{P_{2}}{P_{1}}$

Answer 1

Answer: (B)

$H _{2}\left( P _{1}\right)+2 H ^{+}(1 M ) \rightarrow 2 H ^{+}(1 M )+ H _{2}\left( P _{2}\right)$
$E _{\text {cell }}= E _{\text {cell }}^{0}-\frac{ RT }{2 F } In$
$=0-\frac{ RT }{2 F } In \frac{ P 1}{ P 2}\left[\right.$ for concentration cell, $\left.E _{\text {cell }}^{\circ}=0\right]$
$=\frac{ RT }{2 F } In \frac{ P 1}{ P 2}$