Question

The pressure of hydrogen gas is increased from $1$ atm to $100$ atm. Keeping the $H ^{+}$(1M) constant, the voltage of the hydrogen half-cell at $25^{\circ} C$ will be :

• A. 0.059 V
• B. 0.59 V
• C. 0.0259 V
• D. -0.0591 V

Answer 1

Answer: (D)

$H ^{+}+ e ^{-} \longrightarrow \frac{1}{2} H _{2}( g )(1 atm )$
At 1 atm pressure $E_{\text {red }}=E_{\text {red }}^{\circ}-\frac{0.0591}{1} \log \frac{(1)^{1 / 2}}{1}$
$E_{ red }= E _{ red }^{\circ}=0$
At $100$ atm pressure
$E_{\text {red }}^{1}=E_{\text {red }}^{0}-\frac{0.0591}{1} \log \frac{(100)^{1 / 2}}{1}$
$E_{\text {red }}^{1}=E_{\text {red }}^{0}-0.0591$
$E_{\text {red }}^{1}=0-0.0591$
$ \Rightarrow -0.0591$