Which of the following will declourise alkaline `KMnO_(4)`solution ?

Options

A. `C_(3)H_(8)`
B. `CH_(4)`
C. `C C l_(4)`
D. `C_(2)H_(2)`

Explanation

To determine which of the given compounds will decolorize alkaline KMnO₄ solution, we need to understand the reactivity of different types of hydrocarbons with this reagent.

### Step-by-Step Solution:

1. **Understanding Alkaline KMnO₄**:
Alkaline KMnO₄ (potassium permanganate) is a strong oxidizing agent that is particularly effective in reacting with unsaturated hydrocarbons, such as alkenes and alkynes.

2. **Identifying the Compounds**:
Let's analyze the compounds given in the question. The compounds typically include alkenes, alkynes, and alkanes.

3. **Reactivity of Alkenes**:
- Alkenes (CₙH₂ₙ) can react with alkaline KMnO₄. They undergo oxidation to form diols (glycols) and will decolorize the purple color of KMnO₄.

4. **Reactivity of Alkynes**:
- Alkynes (CₙH₂ₙ₋₂) can also react with alkaline KMnO₄. For example, ethyne (C₂H₂) can be oxidized to form oxalic acid (C₂H₂O₄) and will similarly decolorize the KMnO₄ solution.

5. **Reactivity of Alkanes**:
- Alkanes (CₙH₂ₙ₊₂), such as methane (CH₄) and carbon tetrachloride (CCl₄), do not react with alkaline KMnO₄ as they are saturated hydrocarbons. Therefore, they will not decolorize the solution.

6. **Conclusion**:
- Among the given options, only the unsaturated hydrocarbons (alkenes and alkynes) will decolorize the alkaline KMnO₄ solution. Therefore, the correct answer is the alkyne (e.g., C₂H₂).

### Final Answer:
The compound that will decolorize alkaline KMnO₄ solution is **C₂H₂ (ethyne)**.