Which of the following is isolated in pure form

Options

A. `HClO_(4)`
B. `HClO_(3)`
C. `HClO_(2)`
D. HClO

Explanation

To determine which of the given compounds is isolated in pure form, we can analyze each option based on their stability and behavior under certain conditions.

### Step-by-Step Solution:

1. **Analyze HCl (Hydrochloric Acid)**:
- HCl can decompose into Cl2 (Chlorine gas) and H2 (Hydrogen gas) under certain conditions.
- Therefore, HCl is not isolated in pure form.

**Hint**: Check if the compound can decompose into simpler substances.

2. **Analyze HClO2 (Chlorous Acid)**:
- HClO2 undergoes auto-oxidation, which means it can convert into HClO (Hypochlorous acid) and HClO3 (Chloric acid).
- Since it can change into other compounds, HClO2 is also not isolated in pure form.

**Hint**: Look for reactions that lead to the formation of other compounds.

3. **Analyze HClO3 (Chloric Acid)**:
- HClO3 can decompose to produce Cl2 when exposed to light, as it acts as an oxidizing agent.
- Thus, HClO3 is not stable enough to be isolated in pure form.

**Hint**: Consider the stability of the compound under various conditions.

4. **Analyze HClO4 (Perchloric Acid)**:
- HClO4 is known for its stability and does not undergo oxidation or reduction easily.
- It remains intact and can be isolated in pure form without decomposing into other substances.

**Hint**: Identify compounds known for their stability and lack of reactivity.

### Conclusion:
The compound that can be isolated in pure form is **HClO4 (Perchloric Acid)**.

### Final Answer:
HClO4 is isolated in pure form.

---