We completed a redox titration of Iodine (formed from 1M Potassium Iodide (KI), 0.1M Potassium Iodate (KIO3) and excess Hydrochloric acid (KCl) against Sodium thiosufate (Nas2O3) It took 25.8cm3 of 0.1 M Nas2O3 to get rid of the formed Iodine. The question asks: Use the equation below to calculate the amount of iodide ions that reacts with each mole of iodate ions in aqueous solution 2S2O32- (aq)+ I2 (aq) 2I- (aq) + S4O62-(aq) and determine the concentration of iodide ions in moldm-3 I am not sure what this is asking me! Do I need to calculate how the Iodine is originally formed? I am really stuck on this one! Please help.