Question

in balancing I3- --- I- + IO3- wat is reduced to what

Answer 1

a)I3 goes from 0 to -1 to form some I-
b) I3 goes from 0 to +5 to form IO3-


so you need five (a) for each (b)

2I3>>5I- + IO3-

yes you need to work on oxygen.

Answer 2

I think I caught the first question early today. Here is what I do. The I3^- just complicates things, at least for me.
IO3^- + I^- ==> I + I
I goes from +5 on the left to zero on the right (only one of the I atoms used on the right).
I^- goes from -1 on the left to zero on the right (the other I atom on the right). Balance those two half equations, then add I^- to both sides to show I3^-.