14.39  [ENDORSED]

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Postby ClaireHW » Wed Feb 21, 2018 7:59 pm

Determine the unknown quantity in each of the following cells:
a) Pt(s) I Hg2 (1.0 bar) I H+ (pH=?) II Cl- (aq, 1.0 M) I Hg2Cl2(s) I Hg(l), E=0.33V
b) C(gr) I Cl2(g, 1 bar) I Cl- (aq, ?) II MnO4- (aq, 0.010 M), H+ (pH=4.0), Mn2+ (aq, 0.10 M) I Pt(s), E=-0.30

I'm specifically confused about part b and the order the products and reactants are organized with in the equation and how to tell which are which in the cell diagram.


(Claire Woolson Dis 1K)

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Re: 14.39  [ENDORSED]

Postby Chem_Mod » Thu Feb 22, 2018 8:42 am

Looking at part b, we knows the leftmost compartment (to the left of the salt bridge) is where the oxidation takes place (anode) and the rightmost where reduction takes place (cathode).

So we need to look up a half-reaction in Appendix 2B that matches the oxidation on the left. The reaction we are interested in is 2Cl- --> Cl2 + 2e- (written as an oxidation here, it will be written as a reduction in the appendix). None of the components are conductive, so we have to place a conductive electrode in there. We choose graphitic carbon over platinum to avoid it's oxidation and potential reaction with the Cl2.

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Re: 14.39

Postby Leila_4G » Fri Feb 28, 2020 11:04 pm

I am having trouble finding the n value in part b. I keep getting 10 or 5. Do you know how to do this part? Thank you!

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