When `MnO_2` is fused with KOH and `O_2`, what is the product formed and its colour?
`MnO_2+KOH +O_2 to"_________" + H_2O`

Options

A. MnO - coloureless
B. `K_2MnO_4` - purple
C. `K_2MnO_4` -dark green
D. `MnO_3` -black

Explanation

To solve the question, we need to analyze the reaction between manganese dioxide (MnO₂), potassium hydroxide (KOH), and oxygen (O₂) during fusion.

### Step-by-Step Solution:

1. **Identify the Reactants**:
The reactants in the reaction are MnO₂, KOH, and O₂.

2. **Understand the Fusion Process**:
When these compounds are fused together, they undergo a chemical reaction. Fusion typically involves heating the reactants to form new compounds.

3. **Determine the Products**:
In this case, the reaction between MnO₂, KOH, and O₂ leads to the formation of potassium manganate (K₂MnO₄) and water (H₂O). The balanced reaction can be represented as:
\[ \text{MnO}_2 + 2 \text{KOH} + \text{O}_2 \rightarrow \text{K}_2\text{MnO}_4 + 2 \text{H}_2\text{O} \]

4. **Identify the Color of the Product**:
Potassium manganate (K₂MnO₄) is known to have a dark green color.

5. **Final Answer**:
Therefore, the product formed when MnO₂ is fused with KOH and O₂ is K₂MnO₄, and its color is dark green.

### Complete Reaction:
\[ \text{MnO}_2 + 2 \text{KOH} + \text{O}_2 \rightarrow \text{K}_2\text{MnO}_4 + 2 \text{H}_2\text{O} \]

### Answer:
K₂MnO₄ (dark green)

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