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Question 13.39b

Posted: Mon Feb 09, 2015 10:26 pm
by Justin Le 2I
For this problem, why is n=1 instead of 2? I used 2 because of the standard reaction 2 H+ + 2e- -> H2.

Re: Question 13.39b

Posted: Mon Feb 09, 2015 11:05 pm
by Chem_Mod
The cell reaction is H+(aq, 1*10-3) = H+(aq, 1*10-4), so for one mole of total cell reaction, there are 1 mole of electrons being transferred. If you use 2H+ + 2e- = H2 as the half reaction, then the total reaction should be 2H+(aq, 1*10-3) = 2H+(aq, 1*10-4). There are indeed 2 moles of electrons being transferred, but the reaction quotient in the Nernst equation should also be squared, which will cancel out that 2.