Question

Alkaline oxidative fusion of \(MnO_2\) gives “A” which on electrolytic oxidation in alkaline solution produces B. A and B respectively are:

• A. Mn$_2$O$_7$ and MnO$_4^-$
• B. MnO$_4^{2-}$ and MnO$_4^-$
• C. Mn$_2$O$_3$ and MnO$_4^{2-}$
• D. MnO$_4^{2-}$ and Mn$_2$O$_7$

Answer 1

The Correct Option is B

To solve this problem, we need to understand the chemical transformations taking place. The process described involves two main steps: the alkaline oxidative fusion of \( \text{MnO}_2 \) and subsequent electrolytic oxidation.

1. First, let's analyze the alkaline oxidative fusion of \( \text{MnO}_2 \):
   In a strongly alkaline medium, \( \text{MnO}_2 \) undergoes fusion to form manganate ions. The reaction is as follows: \(\text{MnO}_2 + \text{OH}^- \rightarrow \text{MnO}_4^{2-}\). In this reaction, the oxidation state of manganese changes from +4 in \( \text{MnO}_2 \) to +6 in \( \text{MnO}_4^{2-} \).
2. Next, consider the electrolytic oxidation of \( \text{MnO}_4^{2-} \):
   During electrolytic oxidation in an alkaline solution, the manganate ion (\( \text{MnO}_4^{2-} \)) is further oxidized to permanganate ion (\( \text{MnO}_4^- \)). The reaction is as follows: \(\text{MnO}_4^{2-} \rightarrow \text{MnO}_4^-\). Here, the oxidation state of manganese increases from +6 in \( \text{MnO}_4^{2-} \) to +7 in \( \text{MnO}_4^- \).

Based on these reactions, we can determine that "A" is \( \text{MnO}_4^{2-} \), and "B" is \( \text{MnO}_4^- \).

Thus, the correct answer is the option that identifies A and B as \( \text{MnO}_4^{2-} \) and \( \text{MnO}_4^- \) respectively.

Correct Option: \( \text{MnO}_4^{2-} \) and \( \text{MnO}_4^- \).

Answer 2

The process described involves the oxidative reactions of manganese compounds in alkaline solutions.

Alkaline Oxidative Fusion of \(MnO_2\): When \(MnO_2\) is subjected to oxidative fusion in an alkaline medium, it can form \(MnO_4^{2-}\) (manganate ion) under alkaline conditions. The reaction can be represented as:

\(2MnO_2 + 2OH^- + O_2 \rightarrow 2MnO_4^{2-} + H_2O\).

Electrolytic Oxidation of Product A: The product A formed from the oxidative fusion of \(MnO_2\) can be oxidized electrolytically in alkaline solution to form \(MnO_4^-\) (permanganate ion). The overall reaction is:

\(MnO_2 + 2e^- \rightarrow MnO_4^-\).

Thus, the products A and B formed in the given reaction sequence are: A = \(MnO_4^{2-}\) and B = \(MnO_4^-\).