Question

What is the potential of the cell containing two hydrogen electrodes as represented below?
Pt; $\frac{1}{2} H _2( g )\left| H _2 O \right|\left| H ^{\oplus}(0.001\, M )\right| 1 / 2 H _2( g ) Pt$

• A. $-0.236\, V$
• B. $-0.0591 \, V$
• C. $0.236\, V$
• D. $0.0591 \, V$

Answer 1

Answer: (C)

$E_{\text {cell }}=\frac{0.0591}{1} \log \frac{\left[ H ^{\oplus}\right]_{ RHS }}{\left[ H ^{\oplus}\right]_{ LHS }}$
$\left[\text { For } H _2 O ,\left[ H ^{\oplus}\right]=[ \overset{\ominus}{O}H ]=10^{-7} M \right]$
$=0.059 \log \frac{10^{-3}}{10^{-7}}=0.59 \times 4=0.236 V$
Or $E_{\text {cell }}=-0.059\left( pH _{ c }- pH \right)=-0.059(3-7)=$
$0.236\, V$