When `MnO_(2)` fused with `KOH`, a coloured compound is formed . The product and its colour is:

Options

A. `K_(2)MnO_(4)`, green
B. `Mn_(2)O_(3)`brown
C. `Mn_(2)O_(4)`, black
D. `KMnO_(4)`, purple

Explanation

To solve the question, we need to identify the product formed when manganese dioxide (MnO₂) is fused with potassium hydroxide (KOH) and determine its color.

### Step-by-Step Solution:

1. **Identify the Reactants**: The reactants given are manganese dioxide (MnO₂) and potassium hydroxide (KOH).

2. **Understand the Reaction Conditions**: The reaction occurs upon fusion, which typically means heating the reactants together. The presence of oxygen is also noted, which may facilitate the oxidation process.

3. **Write the Reaction**: The reaction can be represented as follows:
\[ 2 \text{MnO}_2 + 4 \text{KOH} + \text{O}_2 \rightarrow 2 \text{K}_2\text{MnO}_4 + 2 \text{H}_2\text{O} \]
Here, manganese dioxide reacts with potassium hydroxide and oxygen to form potassium manganate (K₂MnO₄) and water.

4. **Identify the Product**: The product formed in this reaction is potassium manganate (K₂MnO₄).

5. **Determine the Color of the Product**: Potassium manganate (K₂MnO₄) is known to be green in color due to the presence of the manganate ion (MnO₄²⁻), which exhibits a green color due to metal-to-ligand charge transfer.

### Final Answer:
The product formed when MnO₂ is fused with KOH is potassium manganate (K₂MnO₄), and its color is green.

---