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 `I_(2)` consumed 45.0 " mL of " thiosulphate solution to decolourise the blue starch-iodine complex. Calculate the molarity of the sodium thosulphate solution.

Options

A. `0.0623`
B. `6.23`
C. `3.001`
D. `1.23`

Answer

A

Explanation

`IO_(3)^(-) +5I^(-) +6H^(+) rarr 3I_(2) +3H_(2)O`
`2Na_(2)S_(2)O_(3)+I_(2) rarr 2NaI +Na_(2)S_(4) O_(6)`
1 mole `IO_(3)^(-) -=3` moles `I_(2) -=6` moles `Na_(2)S_(2)O_(3)`
`:.` moles of hypo reacted `=(0.1)/(2.14) xx 6`
Molarity of hypo `=(0.1 xx 6 xx 1000)/(214 xx 45) = 0.0623M`