An aqueous solution containing 0.10 g KIO_(3) (formula weight =214.0) was treated with an excess of KI solution. The solution was acidified with HCl. The liberated iodine consumed 45.0 mL of thiosulphate solution to decolourise the blue starch-iodine complex. Calculate the molarity of the sodium thiosulphate solution.

An aqueous solution containing 0.10 g KIO_(3) (formula weight =214.0)

1.	An aqueous solution containing 0.10 g KIO_(3) (formula weight =214.0) was treated with an excess of KI solution. The solution was acidified with HCl. The liberated iodine consumed 45.0 mL of thiosulphate solution to decolourise the blue starch-iodine complex. Calculate the molarity of the sodium thiosulphate solution.
Answer» SOLUTION :`2KIO_(3)+10KI+12HCl to 12 KCl +6I_(2)+6H_(2)O` [`2Na_(2)S_(2)O_(3)+I_(2) to 2NaI+Na_(2)S_(4)O_(6)]xx6` `overlineul(underset(2"moles")(2KIO_(3))+10KI+underset(12"moles")(12Na_(2)S_(2)O_(3))+12HCl to 12KCl+12NaI+6Na_(2)S_(4)O_(6)+6H_(2)O)` No. of moles of `KIO_(3)=(0.10)/(214)` No. of moles of `Na_(2)S_(2)O_(3)` REQUIRED for `(0.10)/(214)` moles of `KIO_(3)` `=(12)/(2)xx(0.10)/(214)=(0.60)/(214)` Molarity of `Na_(2)S_(2)O_(3)=(0.6)/(214)xx(1000)/(45)=0.0623 M`