1. The problem statement, all variables and given/known data How many milliliters of Cl2 gas, measured at 28.0 °C and 750 torr, are needed to react with 18.5 mL of 0.173 M NaI if the I- is oxidized to IO3- and the Cl2 is reduced to Cl-? 2. Relevant equations 3. The attempt at a solution So the molar mass is .0030906 mol NaI. Now I need to find out how many moles of Cl2 are needed to react completely with that. So I need the balanced chemical equation. Cl2 + NaI --> IO3- + Cl- Redox: 2e- + Cl2 --> 2Cl- NaI --> IO3- + Na+ This is where I get stuck. I can't balance NaI as a redox reaction because I don't know the charges on that side. How do I balance the second part of the reaction?