Chemistry

Problem

Titration of

\text{I}_2

produced from 0.1045 g of primary standard

\text{KIO}_3

required 30.72 mL of sodium thiosulphate as shown below:

\text{IO}_3^- + 5\text{I}^- + 6\text{H}^+ \longrightarrow 3\text{I}_2 + 3\text{H}_2\text{O}

\text{I}_2 + 2\text{S}_2\text{O}_3^{2-} \longrightarrow 2\text{I}^- + \text{S}_4\text{O}_6^{2-}

The molarity of sodium thiosulphate ion is : a. 0.095 b. 0.079 c. 0.084 d. 0.064