## 14.11

Emily Glaser 1F
Posts: 156
Joined: Thu Jul 27, 2017 3:01 am

### 14.11

can someone do step by step of part d. I don't understand why, in the solutions manual, it says:

O2 +2H2O + 4e- --> 4OH- for the cathode (positive E value). OH- is listed before O2, so shouldn't the O2 be on the right side and OH on the left with a positive E value

Clara Rehmann 1K
Posts: 53
Joined: Fri Sep 29, 2017 7:03 am

### Re: 14.11

Yes, but the catch with this problem is that the battery does not have a positive voltage, as the Eº of the anode is greater than that of the cathode.

Pt(s) | O2(g) | H+(aq) || OH-(aq) | O2 (g) | Pt(s)

Overall reaction: 4H2O(l) → 4H+(aq) + 4OH-(aq)

Anode: O2(g) + 4H+(aq) → 2H2O(l) +1.23 V
Cathode: O2(g) + 2H2O(l) + 4e- → 4OH-(aq) +.4 V

Eº = Eºcathode - Eºanode = .4 V - 1.23 V = -.83 V

904676178
Posts: 5
Joined: Fri Jun 17, 2016 11:28 am

### Re: 14.11

Clara Rehmann 1K wrote:Yes, but the catch with this problem is that the battery does not have a positive voltage, as the Eº of the anode is greater than that of the cathode.

Pt(s) | O2(g) | H+(aq) || OH-(aq) | O2 (g) | Pt(s)

Overall reaction: 4H2O(l) → 4H+(aq) + 4OH-(aq)

Anode: O2(g) + 4H+(aq) → 2H2O(l) +1.23 V
Cathode: O2(g) + 2H2O(l) + 4e- → 4OH-(aq) +.4 V

Eº = Eºcathode - Eºanode = .4 V - 1.23 V = -.83 V

How did you know what the anode is? Isn't the cathode supposed to be the one with the greater positive Eº?