High altitude balloons used by the weather office to measureO3 levels in the atmosphere also use a similar idiometric titration where the iodine liberated is measured by back titration with sodium thiosulfate. In this case the iodine isgenerated by oxidation of iodid by ozone:
O3 (g) + I- (aq) + 2H+ (aq)→ I2 (aq) + O3 (g) + H2O(l)
If 10,000L of air were bubbled through an acidic iodid solution atSTP and was then back titrated with 19.4 mL of a 1.2 x10-4MNa2S2O3 solution to reach equivalence, what is the concentratin of ozone in that sample of air in ppm?