Discussion Forum

1)

Consider the single electrode process  $4H^{+}+4e^{-}\rightleftharpoons 2H_{2}$ catalysed by a platinum black electrode in HCl

electrolyte. The potential of the electrode is -0.059 V   SHE.  What is the concentration of the acid in the hydrogen half cell if the $H_{2}$ pressure is 1 bar? 

$4H^{+}+4e^{-}\rightleftharpoons 2H_{2}$

Answer:

Option C

Explanation:

$4H^{+}+4e^{-}\rightleftarrows 2H_{2}$

 $E= E^{0}-\frac{0.059}{n}\log \frac{pH_{2}}{[H^{+}]^{4}}$

$-0.059=0-\frac{0.059}{4}\log \frac{1}{[H^{+}]^{4}}$

 $=[H^{+}]=10^{-1}=0.1M$