Question

Consider the cell :
$Pt|H_2\left(p_{1}atm\right)|H^{\oplus }\left(x_{1}M\right)||H^{\oplus }\left(x_{2}M\right)|H_2\left(p_{2}atm\right)|Pt$. The cell reaction be spontaneous if:

• A. $p_1=p_2$ and $x_1>x_2$
• B. $p_1=p_2$ and $x_1<x_2$
• C. $x_1=x_2$ and $p_1>p_2$
• D. $x_1=x_2$ and $p_1<p_2$

Answer 1

Answer: (B), (C)

The correct options are
B $p_1=p_2$ and $x_1<x_2$
C $x_1=x_2$ and $p_1>p_2$

$E_{Red}=-0.059[pH+\frac{log.p{H}_2}{2}]$

$\Rightarrow E_{cell}=0.059[p{H}_a-p{H}_c+\frac{1}{2}log\frac{(p{H}_2{)}_a}{(p{H}_2{)}_c}]V$

$E_{cell}>0$, when $p_1=p_2$ and $x_1<x_2$ or when $x_1=x_2$ and $p_1>p_2$

Hence, options B and C are correct.