J.R. S. answered 12/24/19
Ph.D. University Professor with 10+ years Tutoring Experience
I'm guessing you are asking how to balance this? Correct?
Since there are OH- ions on the right side of the equation, this indicates the reaction is taking place (and being balanced) in alkaline conditions.
IO3- ===> IO- initial equation
IO3- ===> IO- + 2H2O to balance the O atoms
IO3- + 4OH- + 4H+ ===> IO- + 2H2O + 4OH- to balance the H atoms using base
IO3- + 4OH- + 4H+ +4e- ===> IO- + 2H2O + 4OH- to balance the charge
Canceling and reducing we end up with...
IO3- + 2H2O + 4e- ==> IO- + 4OH-
So answer would be (B) 2 H2O, 4e- and 4 OH-