$20 \mathrm{mL}$ 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 $\mathrm{KI}$ using starch as an indicator. The molarity of ${\mathrm{Cu}}^{2+}$ is found to be $\_\_\_\_\_\times {10}^{-2}\mathrm{M}$ (nearest integer)

Given : $$\begin{gathered} 2{\mathrm{Cu}}^{2+}+4{\mathrm{I}}^{-}\to {\mathrm{Cu}}_2{\mathrm{I}}_2+{\mathrm{I}}_2 \\ {\mathrm{I}}_2 + 2{\mathrm{S}}_2{\mathrm{O}}_3^{-2} \to 2{\mathrm{I}}^{—} + {\mathrm{S}}_4{\mathrm{O}}_6^{-2} \end{gathered}$$

Match List-I with List-II, match the gas evolved during each reaction.

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For kinetic study of the reaction of iodide ion with ${\mathrm{H}}_2{\mathrm{O}}_2$ at room temperature :

(A) Always use freshly prepared starch solution.

(B) Always keep the concentration of sodium thiosulphate solution less than that of $\mathrm{KI}$ solution.

(C) Record the time immediately after the appearance of blue colour.

(D) Record the time immediately before the appearance of blue colour.

(E) Always keep the concentration of sodium thiosulphate solution more than that of $\mathrm{KI}$ solution.

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