need help to balance half reaction in basic solution

Question

IO3 to I2

Answer 1

The problem most students have with an equation like this is "they don't start of even." That is you must make the I atoms the same BEFORE you start balancing.
2IO3^- == I2.
That's step 1.
2. Balance electrons change.
10+ total on IO3^- and zero total on I2; therefore,
2IO3^- + 10e ==> I2

3. Now count up the charge on each side and add OH^- ions (add H^+ for acid solutions). I see -12 on the left and zero on the right.
2IO3^- + 10e ==> I2 + 12OH^-

4. Add H2O to balance.
2IO3^- + 10e + 6H2O ==> I2 + 12OH^-