Which of the following samples of reducing agents is/are chemically equivalent to 25mL of 0.2 N $KMn{O}_4$ to be reduced to $M{n}^{2+}$ and water?
 

The reducing agents is/are chemically equivalent to 25 mL of 0.2 N $KMn{O}_4$ to be reduced to $M{n}^{2+}$ and water.

milli equivalent of ${\mathrm{KMnO}}_4$

$$\begin{gathered} =25\times 0.2 \\ =5 \end{gathered}$$

(a) $25\times 0.2\times 1$        (b) $50\times 0.1\times 3$

(c) $25\times 0.1\times 2$        (d) $25\times 0.1\times 2$

Hence, the correct option is a, c and d.