Q 11 :    

The pressure of H2 required to make the potential of H2 electrode zero in pure water at 298 K is                [2016]
 

  • 10-10 atm

     

  • 10-4 atm

     

  • 10-14 atm

     

  • 10-12 atm

     

(3)

pH = 7 for water.  

-log[H+]=7    [H+]=10-7

2H(aq)++2e-  H2(g)

Ecell=Ecell-0.05912logpH2[H+]2

0=0-0.05912logpH2(10-7)2

logpH2(10-7)2=0    pH2(10-7)2=1                         [log1=0]

pH2=10-14 atm