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

Options

A. `K_2MnO_4` , green
B. `KMnO_4` , purple
C. `Mn_2O_3` brown
D. `MnO_2`, black

Answer

To solve the question regarding the reaction of `MnO2` with `KOH`, we will follow these steps:

### Step 1: Identify the Reactants
The reactants in this reaction are manganese dioxide (`MnO2`) and potassium hydroxide (`KOH`).

**Hint:** Look for the compounds involved in the reaction and their states.

### Step 2: Understand the Reaction Conditions
The reaction occurs when `MnO2` is fused with `KOH` in the presence of air. This indicates that oxygen from the air may participate in the reaction.

**Hint:** Consider the role of oxygen in oxidation reactions.

### Step 3: Write the Chemical Equation
The reaction can be represented as follows:
\[ \text{MnO}_2 + 4 \text{KOH} + \text{O}_2 \rightarrow 2 \text{K}_2\text{MnO}_4 + 2 \text{H}_2\text{O} \]

**Hint:** Ensure that you balance the equation correctly by counting the number of atoms of each element on both sides.

### Step 4: Identify the Product
From the balanced equation, the product formed is potassium manganate, which is represented as `K2MnO4`.

**Hint:** Look for the product that contains manganese and potassium.

### Step 5: Determine the Color of the Product
The color of potassium manganate (`K2MnO4`) is typically described as green or purple-green.

**Hint:** Recall the common colors associated with transition metal compounds, particularly those of manganese.

### Final Answer
The product formed when `MnO2` is fused with `KOH` is `K2MnO4`, and its color is green (or purple-green).

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