Electrolysis

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Rebecca Chen 3F
Posts: 32
Joined: Fri Sep 25, 2015 3:00 am

Electrolysis

Postby Rebecca Chen 3F » Thu Feb 04, 2016 3:00 pm

Textbook problem 14.55 states "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 or passivity at the electrodes, what is the minimum potential that must be supplied to the cell for the onset of electrolysis?"
How do you know which reduction and oxidation reactions to choose? The solution manual says to choose the most positive (least negative) reduction potential for the cathode, yet picks Ni2+ +2e- -> Ni(s), E=-0.23 V while the reduction for SO4 2- + 4H+ +2e- -> H2SO3 +H2O has a E of +.23 V. Why choose Ni and why choose the most positive reduction potential?

Rambod Meshgi 3J
Posts: 21
Joined: Fri Sep 25, 2015 3:00 am

Re: Electrolysis

Postby Rambod Meshgi 3J » Fri Feb 05, 2016 8:21 pm

The cathode must be a solid piece of metal such as Ni where as SO4 is a salt and couldn't be made into a cathode.


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