For estimating ozone in the air, a certain volume of air is passed through an . Alkaline Kl solution when O_(2)is evolved and iodide is oxidized to iodine . When such a solution is acidified , free iodine is evolved which can be titrated with standard Na_(2)S_(2)O_(3) . Solution : in an experiment, 10 L ari at 1 atm and 27^(@) C were passed through an alkaline Kl solution , and at the end, the iodine was entrapped in a solution which on titration as above required 1.5 ml of 0.01 N Na_(2)S_(2)O_(3) solution. Calculate volume percentage of ozone in the sample.

For estimating ozone in the air, a certain volume of air is passed thr

1.	For estimating ozone in the air, a certain volume of air is passed through an . Alkaline Kl solution when O_(2)is evolved and iodide is oxidized to iodine . When such a solution is acidified , free iodine is evolved which can be titrated with standard Na_(2)S_(2)O_(3) . Solution : in an experiment, 10 L ari at 1 atm and 27^(@) C were passed through an alkaline Kl solution , and at the end, the iodine was entrapped in a solution which on titration as above required 1.5 ml of 0.01 N Na_(2)S_(2)O_(3) solution. Calculate volume percentage of ozone in the sample.
Answer» Solution :The chemical REACTION is , `H_(2)O +Kl + O_(3) tol_(2) + O_(2) + KOH ` Milliequivalents of iodine = Milliequivalents of Kl = MILLI equivalents of `O_(3)` reacted Milliequivalnets of `Na_(2)S_(2)O_(3) = 1.5 xx 0.01 = 1.5 xx 10^(-2)` Millimoles of iodine ` = (1.5 xx 10^(-2))/2 = 7.5 xx 10^(-3)"" [ :." n-factor for iodine " =2]` Millimoles of ozone ` = 7.5 xx 10^(-3)` Volume of ozone ` = (nRT)/P = (7.5 xx 10^(-6) xx 0.0821 xx 300)/1 = 184.725 xx 10^(-6) ` litre Volume PER cent of ozone ` = (184 .725 xx 10^(-6))/10 xx 100 = 1.847 xx 10^(-3)`