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Postby donnanguyen1d » Mon Mar 12, 2018 10:05 pm

a) The standard Gibbs free energy of formation of Tl3(aq) is 215 kJmol1 at 25 C. Calculate the standard potential of the Tl3/Tl couple. (b) Will Tl disproportionate in aqueous solution?

Why did they reverse the reaction in the solutions? is it so that the gibbs free would become negative? how do we know we would have to reverse it.

Justin Yu 3H
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Re: 14.33

Postby Justin Yu 3H » Tue Mar 13, 2018 4:54 am

The reaction between the cathode and anode needs to be spontaneous for the cell to work and have a positive voltage, which implies a negative gibbs free energy. Since the formation of Ti3+ has a positive gibbs free energy, you have to reverse it, then plug it into G = -nFE to find the standard potential.

Justin Bui 2L
Posts: 51
Joined: Fri Sep 29, 2017 7:06 am

Re: 14.33

Postby Justin Bui 2L » Sat Mar 17, 2018 7:27 pm

I agree with Justin and you have the right idea. The reaction needs to be spontaneous for it to run, so that means delta G needs to be negative, which is the opposite of what's provided.

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