Half Reaction: Balance H2O and OH-

Question

When the following half reaction is balanced under basic conditions, what are the coefficients of the species shown?

 _____SnO₃^2- +  _______H₂O   ______SnO₂^2- +  ______OH^-

In the above half reaction, the oxidation state of tin changes from ___ to ___.

Answer 1

SnO₃^2- ==> SnO₂^2- ... unbalanced

SnO₃^2- ==> SnO₂^2- + H₂O ... balance for Sn and O

SnO₃^2- +2H2O ==> SnO₂^2- + H₂O + 2OH^- ... balanced for Sn, O and H

SnO₃^2- +2H₂O + 2e- ==> SnO₂^2- + H₂O + 2OH^- ... balanced for mass and charge

___1_SnO₃^2- +  ___2___H₂O   ___1__SnO₂^2- +  ___2__OH^-

In the above half reaction, the oxidation state of tine changes from 4+ to 2+