Pyrolusite ore on oxidation with `KCIO_(3)//KNO_(3)` in basic medium produces dark green coloured compound `(A)`, which on electrolysis produces a purple coloured compound `(B)`. The purple coloured rhombic prisms. It shows different reactions in different mediums.
Excess of compounds (B) on heating with conc. `H_(2)SO_(4)` gives an explosive oil (C ), which on heating decomposes to gives another compound (D ) along with oxygen.
Identify (D).

Options

A. `Mn_(2)O_(7)`
B. `MnO_(2)`
C. `MnSO_(4)`
D. `Mn_(2)O_(3)`

Answer

To solve the problem step by step, we will follow the sequence of reactions and identify the compounds involved.

### Step 1: Identify the Pyrolusite Ore
Pyrolusite ore is primarily composed of manganese dioxide (MnO₂).

### Step 2: Reaction with KClO₃ in Basic Medium
When pyrolusite (MnO₂) is oxidized with potassium chlorate (KClO₃) in a basic medium, it produces a dark green colored compound. The reaction can be represented as follows:

\[ 2 \text{MnO}_2 + 2 \text{KClO}_3 + 2 \text{OH}^- \rightarrow \text{Mn}_2\text{O}_7 + 2 \text{KCl} + 2 \text{H}_2\text{O} \]

The dark green colored compound produced here is manganese heptoxide (Mn₂O₇).

### Step 3: Electrolysis of Compound A
The dark green compound (Mn₂O₇) undergoes electrolysis, which produces a purple colored compound. The electrolysis of Mn₂O₇ leads to the formation of potassium permanganate (KMnO₄), which is the purple colored compound (B).

### Step 4: Reaction of Compound B with Concentrated H₂SO₄
When excess potassium permanganate (KMnO₄) is heated with concentrated sulfuric acid (H₂SO₄), it produces an explosive oil (C). The reaction can be represented as:

\[ 2 \text{KMnO}_4 + 3 \text{H}_2\text{SO}_4 \rightarrow \text{Mn}_2\text{O}_6 + \text{K}_2\text{SO}_4 + 2 \text{H}_2\text{O} + 2 \text{O}_2 \]

The explosive oil produced in this reaction is manganese hexoxide (Mn₂O₆).

### Step 5: Decomposition of Compound C
The explosive oil (Mn₂O₆) decomposes upon heating to give another compound (D) along with oxygen. The decomposition reaction can be represented as:

\[ 2 \text{Mn}_2\text{O}_6 \rightarrow 4 \text{MnO}_2 + 3 \text{O}_2 \]

Here, the compound D produced is manganese dioxide (MnO₂).

### Conclusion
Thus, the compound D identified in the problem is **manganese dioxide (MnO₂)**.

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