Which of the following statement(s) is/are correct?

Options

A. Chlorine dioxide `(ClO_(2))` is powerful oxidising agent but bleaching action is lower than `Cl_(2)`
B. `ClO_(2)` in alkaline solution undergoes disproportionation
C. `ClO_(2)` is diamagnetic in nature
D. `ClO_(2)` is a yellow gas but deep red liquid

Explanation

To determine which of the statements regarding chlorine dioxide (ClO2) are correct, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement 1: Chlorine dioxide (ClO2) is a powerful oxidizing agent, but its bleaching action is lower than chlorine.**
- **Analysis**: Chlorine dioxide (ClO2) is indeed a powerful oxidizing agent. However, its bleaching power is actually much higher than that of chlorine (Cl2). In fact, ClO2 has a bleaching power that is approximately 30 times greater than that of Cl2.
- **Conclusion**: This statement is **incorrect**.

2. **Statement 2: ClO2 in alkaline solution undergoes disproportionation.**
- **Analysis**: Disproportionation is a reaction where a single substance is both oxidized and reduced. In an alkaline solution, ClO2 reacts with sodium hydroxide (NaOH) to form sodium hypochlorite (NaClO) and sodium chlorate (NaClO3). In this reaction, chlorine in ClO2 goes from an oxidation state of +4 to +1 (reduction) and +5 (oxidation), confirming that disproportionation occurs.
- **Conclusion**: This statement is **correct**.

3. **Statement 3: ClO2 is diamagnetic in nature.**
- **Analysis**: To determine if ClO2 is diamagnetic or paramagnetic, we need to examine its electron configuration. ClO2 has an unpaired electron, which makes it paramagnetic. A substance is diamagnetic if all its electrons are paired. Since ClO2 has unpaired electrons, it is not diamagnetic.
- **Conclusion**: This statement is **incorrect**.

4. **Statement 4: ClO2 is a yellow gas but a deep red liquid.**
- **Analysis**: Chlorine dioxide is known to be a yellow gas at room temperature and turns into a deep red liquid when cooled or pressurized. This is a well-documented property of ClO2.
- **Conclusion**: This statement is **correct**.

### Final Conclusion:
The correct statements are **2 and 4**.