Question

Assertion (A) In the reaction between potassium permanganate and potassium iodide, permanganate ions act as oxidising agent.
Reason (R) Oxidation state of manganese changes from $+2$ to $+7$ during the reaction.

• A. Both $A$ and $R$ are correct; $R$ is the correct explanation of $A$.
• B. Both $A$ and $R$ are correct; $R$ is not the correct explanation of $A$.
• C. $A$ is correct; $R$ is incorrect.
• D. $A$ is incorrect; $R$ is correct.

Answer 1

Answer: (C)

The reaction of potassium permanganate and potassium iodide is as follows :
$10 KI +2 K\overset{+7}{Mn} O _{4}+8 H _{2} SO _{4} \longrightarrow 2 \overset{+2}{Mn}SO _{4}+6 K _{2} SO _{4}+8 H _{2} O +5 I _{2}$
Oxidation state of Mn decreases from $+7$ to $+2$.
Thus, $A$ is correct but $R$ is incorrect.