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Postby Maria1E » Sat Feb 17, 2018 2:27 pm

Calculate E for each of the following concentration cells:
b) Pt(s) I H2 (g, 1 bar) I H+ (aq, pH = 4.0) II H+ (aq, pH = 3.0) I H2 (g, 1 bar) I Pt(s)

The solution manual states that n = 1. Can someone please explain why this is? I thought that the 2 half-reactions were 2H+ + 2e --> H2 and H2 --> 2H+ + 2e. After you balance the H's, wouldn't n = 2?

William Satyadi 2A
Posts: 31
Joined: Sat Jul 22, 2017 3:00 am

Re: 14.41(b)

Postby William Satyadi 2A » Sun Feb 18, 2018 3:36 am

Hey! I don't have the solutions manual so I can't see that it says n=1, but I did find a way to solve it using the same set up as you did. Using the Nernst equation, I got . pH is a measure of H+, and we can use logs to find the H+ concentration. so . You also need to remember that for reaction quotients, the coefficients are raised to the power, so our final equation is giving an answer rounding to +0.06V.

Hope this is of some help!

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