RE-NEET 2024 Chemistry Oxidation States MCQ Question

Explanation

Chapter: Redox Reactions

Find the oxidation state of Mn in each manganese species:

• MnO₄²⁻ (manganate): $x + 4(-2) = -2$ $\boxed{x=+6}$

• MnO₄⁻ (permanganate): $x + 4(-2) = -1$ $\boxed{x=+7}$

• MnO₂: $x + 2(-2) = 0$ $\boxed{x=+4}$

So, the oxidation states shown in the reaction are:

$$\boxed{+6,\ +7,\ +4}$$

From the given options, the oxidation states not shown are:

$$\boxed{+2\text{ and }+3}$$

Therefore:

• B = +2
• E = +3

Correct Answer: (d) B and E only ✅

Quick NEET Trick: For $MnO_4^{2-}$, $Mn=+6$; for $MnO_4^-$, $Mn=+7$; for $MnO_2$, $Mn=+4$. Eliminate these three → +2 and +3 remain.