## 6O.1

Ryan Chang 1C
Posts: 105
Joined: Sat Aug 24, 2019 12:17 am

### 6O.1

A 1.0 m NiSO4(aq) solution was electrolyzed by using inert electrodes. Write (a) the cathode reaction; (b) the anode reaction (c) With no overpotential at the electrodes, what is the minimum potential that must be supplied to the cell for the onset of electrolysis?

The solution manual uses the E^o value of +1.23V for the anode. Where do we get this value? I thought we were supposed to use the -0.42V for the reduction of water and 0.82V for the oxidation of water.

Rebecca Remple 1C
Posts: 137
Joined: Wed Sep 18, 2019 12:16 am
Been upvoted: 1 time

### Re: 6O.1

Ryan Chang 1C wrote:A 1.0 m NiSO4(aq) solution was electrolyzed by using inert electrodes. Write (a) the cathode reaction; (b) the anode reaction (c) With no overpotential at the electrodes, what is the minimum potential that must be supplied to the cell for the onset of electrolysis?

The solution manual uses the E^o value of +1.23V for the anode. Where do we get this value? I thought we were supposed to use the -0.4V for the reduction of water and -0.82V for the oxidation of water.

Hi Ryan,

I solved this problem and found that this value is from Appendix 2A. I was also confused about the reasoning for this because it contradicts the 2 given equations. The equation in the appendix is the reverse of one of the given equations, but its value is entirely different. I can't answer this definitively because it is still confusing to me, but I guess the general rule is to use the Appendix information unless the equation 100% matches one of the given examples. If anyone else understands this better, please leave a reply. I hope this helps and good luck on your test!

-Rebecca

Ryan Chang 1C
Posts: 105
Joined: Sat Aug 24, 2019 12:17 am

### Re: 6O.1

Rebecca Remple 1C wrote:
Ryan Chang 1C wrote:A 1.0 m NiSO4(aq) solution was electrolyzed by using inert electrodes. Write (a) the cathode reaction; (b) the anode reaction (c) With no overpotential at the electrodes, what is the minimum potential that must be supplied to the cell for the onset of electrolysis?

The solution manual uses the E^o value of +1.23V for the anode. Where do we get this value? I thought we were supposed to use the -0.4V for the reduction of water and -0.82V for the oxidation of water.

Hi Ryan,

I solved this problem and found that this value is from Appendix 2A. I was also confused about the reasoning for this because it contradicts the 2 given equations. The equation in the appendix is the reverse of one of the given equations, but its value is entirely different. I can't answer this definitively because it is still confusing to me, but I guess the general rule is to use the Appendix information unless the equation 100% matches one of the given examples. If anyone else understands this better, please leave a reply. I hope this helps and good luck on your test!

-Rebecca

Oh ok at least I know where the value comes from. However I agree with you that it is still confusing how we use 1.23V instead of the other given values. If anyone could help answer this it would be greatly appreciated!

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