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Posted: Thu Feb 09, 2017 1:47 pm
by AshleyAguilar_1F
the skeletal equation is:
Cl2 (g) + S2O3 2- (aq) --> Cl- (aq) + SO4 2-

Chorine gas is gaining just 1 electron... okay so in the solutions manual the reduction half-reaction is Cl2 (g) + 2e- --> 2Cl- (aq) and I do not understand why we add 2 electrons; that would make the left side have a charge of 2- and the right side have a charge of 1-.

Re: 14.3

Posted: Thu Feb 09, 2017 1:57 pm
by Matthew_Vargas_2G
Hey Ashley! So for this problem, the reason why there are 2 electrons added to the reactants side is to balance out the total charge from the product side during the half reaction. The skeleton half reaction would be (Cl2 --> Cl-) so we would have to balance out the reaction by putting the coefficient 2 for Cl-. But now we would have (Cl2 --> 2Cl-) with an unbalanced charge. To balance out the 2- on the right side of the reaction (since Cl- has a charge of 1- but then the coefficient multiplies it by two so it has a total of 2-), we would have to add 2 electrons on the left side. Which gives us Cl2 + 2e- --> 2Cl-. Hope this helps!

Re: 14.3

Posted: Thu Feb 09, 2017 5:45 pm
by AshleyAguilar_1F