At the higher temperature bleaching powder

disproportionate to some extent and yield Ca(ClO 3 ) 2 and CaCl 2 . The 10 gm of a pyrollusite sample of 26.1% purity is warmed with 240 ml of 0.5 (M) HCl, the Cl 2 (g) so produced is passed through 3.74 gm of slaked lime (hydrated CaO) containing 40% moisture at 40ºC to produce bleaching powder. The bleaching powder so produced is the "moist bleaching powder". To produce "dry bleaching powder" the "moist bleaching powder" is heated at 80ºC where Ca(OCl)Cl disproportionate to some extent. "Dry bleaching powder" so produced is divided into two equal parts.

To the first part excess of HCl and excess of KI solution added I 2 so produced require 300 ml of 10 –3 (M) Na 2 S 2 O 3 solution.

To the second part excess of CH 3 COOH and excess of KI solution is added the iodine so produced require 200 ml of 10 –3 (M) Na 2 S 2 O 3 solution. It is also seen during drying of moist bleaching powder beside

disproportionation of Ca(OCl)Cl other side reactions also occur "without any gaseous products."

At. wts Mn= 55; Ca = 40

(i) The mass of moist bleaching powder sample

produced is –