A purple coloured solution is made alkaline with KOH and is treated with KI forming potassium iodate. The same solution is acidified with `H_(2) SO_(4)` and again it is treated with Kl. However this time instead of potassium iodate, iodine gas is released. The purple coloured solution is of

Options

A. `K_(2)Cr_(2)O_(7)`
B. `K_(2)Cr_(2)O_(4)`
C. `KMnO_(4)`
D. `K_(2)MnO_(4)`

Answer

To solve the question, we need to identify the purple-colored solution and understand the reactions that occur when it is treated with KOH and KI, and then with H2SO4 and KI.

### Step-by-Step Solution:

1. **Identify the Purple-Colored Solution:**
The purple-colored solution mentioned in the question is potassium permanganate (KMnO4). This compound is well-known for its deep purple color in aqueous solution.

**Hint:** Look for common compounds that are purple in color; potassium permanganate is a classic example.

2. **Reaction with KOH and KI:**
When potassium permanganate (KMnO4) is made alkaline by adding KOH, it reacts with potassium iodide (KI) to form potassium iodate (KIO3) and manganese dioxide (MnO2). The reaction can be represented as follows:
\[ \text{KMnO}_4 + \text{KI} + \text{H}_2\text{O} \rightarrow \text{KIO}_3 + \text{MnO}_2 + \text{KOH} \]

**Hint:** Remember that in alkaline conditions, KMnO4 acts as an oxidizing agent.

3. **Acidification with H2SO4:**
Next, when the solution is acidified with sulfuric acid (H2SO4), the potassium iodate (KIO3) formed in the previous step can react with KI again. In this acidic medium, KMnO4 will again act as an oxidizing agent, but this time it will release iodine gas (I2) instead of forming potassium iodate.

The reaction can be represented as:
\[ \text{KIO}_3 + 6 \text{H}^+ + 5 \text{KI} \rightarrow 3 \text{I}_2 + 3 \text{K}_2\text{SO}_4 + \text{MnSO}_4 + 3 \text{H}_2\text{O} \]

**Hint:** In acidic conditions, iodate ions can be reduced to iodine gas.

4. **Conclusion:**
The purple-colored solution that undergoes these reactions is indeed potassium permanganate (KMnO4). Therefore, the answer to the question is that the purple-colored solution is potassium permanganate.

**Final Answer:** The purple colored solution is potassium permanganate (KMnO4).