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Cell Diagram Order

Posted: Mon Feb 25, 2019 9:44 pm
by ian_haliburton_1f
The textbook has a side comment in the section about cell diagram notation that says “when it is important to emphasize the spatial arrangement of an electrode, the order may reflect that arrangement, as in Cl-(aq)|Cl2(g)|Pt(s).”
I understand why the platinum is on the outside, but otherwise what makes it important to emphasize this order for chemical species like this? Does it have to do with the presence of a gas phase?

Re: Cell Diagram Order

Posted: Mon Feb 25, 2019 11:45 pm
by Emmaraf 1K
There is no solid metal to generate the electric current on that side of the voltaic cell so platinum metal must be present for the half reaction to occur.

Re: Cell Diagram Order

Posted: Tue Feb 26, 2019 1:41 am
by annabel 2A
But why is Cl-(aq) on the left and Cl2(g) on the right?

Re: Cell Diagram Order

Posted: Tue Feb 26, 2019 12:05 pm
by Olivia L 4E
I'm assuming this example was describing the reduction half of the reaction? The form goes as follows oxidation solid (anode) | oxidation gases/liquids | oxidation aqueous solutions || reduction aqueous solutions | reduction gases/liquids | reduction solid (cathode). As you read from outward in, the elements/ions undergo further and further phase changes. It's just a simple and clear method of ordering the reaction.