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)

$H^{+}+e^{-}⟶\frac{1}{2}{H}_2(g)(1atm)$
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
$E_{\text{red }}^1=E_{\text{red }}^0-\frac{0.0591}{1}\log \frac{(100{)}^{1/2}}{1}$
$E_{\text{red }}^1=E_{\text{red }}^0-0.0591$
$E_{\text{red }}^1=0-0.0591$
$\Rightarrow -0.0591$