Question
Chemistry Question on Partial pressure
The pressure of H2 required to make the potential of H2-electrode zero in pure water at 298 K is
A
10−12 atm
B
10−10 atm
C
10−4 atm
D
10−14 atm
Answer
10−14 atm
Explanation
Solution
2H++2e−−>H2(g)
EH+/H2=−20.0591log[H+]2PH2
log[H+]2PH2=0,[H+]2PH2=100=1
PH2=[H+]2
For pure H2O;H+=10−7M
PH2=(10−7)2=10−14 atm