Question
$20 \mathrm{~mL}$ of $0.02\, \mathrm{M}$ hypo solution is used for the titration of $10 \mathrm{~mL}$ of copper sulphate solution, in the presence of excess of KI using starch as an indicator. The molarity of $\mathrm{Cu}^{2+}$ is found to be ____________ $\times 10^{-2} \,\mathrm{M}$. [nearest integer]
Given : $2 \,\mathrm{Cu}^{2+}+4 \,\mathrm{I}^{-} \rightarrow \mathrm{Cu}_{2} \mathrm{I}_{2}+\mathrm{I}_{2}$
$$ \mathrm{I}_{2}+2 \mathrm{~S}_{2} \mathrm{O}_{3}^{2-} \rightarrow 2 \mathrm{I}^{-}+\mathrm{S}_{4} \mathrm{O}_{6}^{2-} $$
Correct Answer
4