In the following reaction mixtures,

I. $\mathrm{Cu} / \mathrm{CuSO}_4+\mathrm{Ag} / \mathrm{Ag}_2 \mathrm{SO}_4$

II. $\mathrm{Zn} / \mathrm{ZnSO}_4+\mathrm{Cu} / \mathrm{CuSO}_4$

copper respectively undergoes

The weight of potassium dichromate (molecular weight $=294$ ) required to prepare 0.04 N of 250 mL solution is

What is the equivalent weight of $\mathrm{KMnO}_4$ in acidic medium? (Molecular weight of $\mathrm{KMnO}_4=158 \mathrm{~g}$ )

$\mathrm{KMnO}_4$ oxidises $\mathrm{C}_2 \mathrm{H}_2 \mathrm{O}_4$ to form $\mathrm{CO}_2$. In which of the following, the reaction will be faster?