Complete and balance the following half-reaction in acidic solution. Be sure to include the proper phases for all species within the reaction

Question

Sn^2+ (aq) --> Sn^4+ (aq)

I know to add H20 on the reactants and H on products but I'm stuck and don't know why.

Answer 1

Sn²⁺(aq) ==> Sn⁴⁺(aq)

For this half reaction, there is NO NEED to add H₂O and H⁺ because there are no hydrogens or oxygens in the reaction. The only thing that needs to be balanced is the charge (+2 going to +4). So, it is simply just a loss of 2 electrons. Here is the balanced half reaction

Sn²⁺(aq) ==> Sn⁴⁺⁽aq) + 2e- .. see how this is balanced for Sn and for charge (+2 on both sides)?