Select the incorrect statement on basis of following conversion :-
`underset("Ore")underset("coloured")underset("Black")(X) underset("air")overset(KOH)tounderset("green")underset("Dark")(Y)overset(H^(o+))tounderset("agent")underset("an oxidising")(Z)+X`

Options

A. X may be `MnO_(2)`
B. Y can be `K_(2)MnO_(4)`
C. Z can be `KMnO_(4)`
D. None of these

Answer

To solve the question, we need to analyze the conversion process described and identify the incorrect statement based on the given reactions.

### Step-by-Step Solution:

1. **Identify the Starting Material (X)**:
- The black colored ore (X) is likely to be manganese dioxide (MnO2).

2. **Reaction with Potassium Hydroxide and Air**:
- When MnO2 reacts with potassium hydroxide (KOH) in the presence of air (oxygen), it produces a green compound (Y).
- The balanced reaction is:
\[ 3 \text{MnO}_2 + 4 \text{KOH} + \text{O}_2 \rightarrow 2 \text{K}_2\text{MnO}_4 + 2 \text{H}_2\text{O} \]
- Here, Y is potassium manganate (K2MnO4), which is green in color.

3. **Reaction of Y with Acid (H+)**:
- When the green compound (Y, K2MnO4) is treated with an acid (H+), it converts to potassium permanganate (KMnO4, Z), which is purple.
- The reaction can be represented as:
\[ 2 \text{K}_2\text{MnO}_4 + 2 \text{H}^+ \rightarrow 2 \text{KMnO}_4 + \text{MnO}_2 + 2 \text{H}_2\text{O} \]

4. **Identify the Compounds**:
- X = MnO2 (black)
- Y = K2MnO4 (green)
- Z = KMnO4 (purple, an oxidizing agent)

5. **Determine the Incorrect Statement**:
- Based on the reactions and the colors of the compounds:
- MnO2 is indeed black.
- K2MnO4 is green.
- KMnO4 is purple and acts as an oxidizing agent.
- Any statement that contradicts these facts would be incorrect.

### Conclusion:
The incorrect statement would be one that misrepresents the colors or the nature of the compounds involved in the reactions.