Why it is not advisable to dissolve `KMnO_(4)` in cold and concentrated `H_(2)SO_(4)`

Answer

To answer the question of why it is not advisable to dissolve KMnO4 in cold and concentrated H2SO4, we can break down the explanation into several steps:

### Step-by-Step Solution:

1. **Understanding the Reactants**:
- KMnO4 (Potassium permanganate) is a strong oxidizing agent.
- H2SO4 (Sulfuric acid) is a strong acid and can act as a dehydrating agent.

2. **Reaction Overview**:
- When KMnO4 is mixed with cold and concentrated H2SO4, a reaction occurs that produces K2SO4 (Potassium sulfate), Mn2O7 (Dichromate), and water (H2O).

3. **Formation of Mn2O7**:
- The reaction leads to the formation of Mn2O7, which is a dark green oily substance. This compound is known to be highly unstable and can be explosive.

4. **Instability of Mn2O7**:
- Mn2O7 is not only unstable but also has a tendency to decompose rapidly. When it decomposes, it produces MnO2 (Manganese dioxide) and oxygen gas (O2).

5. **Vigorous Reaction**:
- The decomposition of Mn2O7 is highly vigorous and exothermic, meaning it releases a significant amount of heat. This can lead to explosive reactions, especially in the presence of concentrated acids.

6. **Conclusion**:
- Due to the formation of the highly explosive Mn2O7 and the vigorous nature of the reaction, it is not advisable to dissolve KMnO4 in cold and concentrated H2SO4. The risks associated with the reaction outweigh any potential benefits.