Select the correct statement `(s)`.

Options

A. `Cr^(2+)` compounds are ionic.
B. They are oxidised to `Cr^(3+)` by air.
C. They are reducing agent in aqueous solution.
D. None is correct.

Explanation

To solve the question "Select the correct statement(s)", we will analyze each of the provided statements regarding the chromium ion (Cr²⁺) and its properties.

### Step-by-Step Solution:

1. **Statement 1: Cr²⁺ compounds are ionic.**
- **Analysis:** Cr²⁺ is a cation, and it typically forms ionic compounds with anions such as sulfate (SO₄²⁻). For example, in chromium(II) sulfate (CrSO₄), the compound is formed from Cr²⁺ and SO₄²⁻, which are both ions. Therefore, this statement is **correct**.

2. **Statement 2: They are oxidized to Cr³⁺ by air.**
- **Analysis:** The oxidation of Cr²⁺ to Cr³⁺ involves the loss of one electron. The electronic configuration of Cr is [Ar] 3d⁵ 4s¹. When Cr²⁺ is formed, it loses two electrons, resulting in a configuration of 3d⁴. When it is oxidized to Cr³⁺, it loses one more electron, resulting in a configuration of 3d³. This process is indeed facilitated by oxygen in the air, making this statement **correct**.

3. **Statement 3: They are reducing agents in aqueous solution.**
- **Analysis:** A reducing agent is a substance that donates electrons and gets oxidized in the process. In aqueous solution, Cr²⁺ can donate an electron to become Cr³⁺, thus acting as a reducing agent. Therefore, this statement is also **correct**.

4. **Statement 4: (Not provided in the transcript, but we assume it exists for completion.)**
- **Analysis:** Without the content of the fourth statement, we cannot analyze it. However, based on the analysis of the first three statements, we can conclude that they are all correct.

### Conclusion:
The correct statements are **Statement 1, Statement 2, and Statement 3**. Therefore, the answer is that options **A, B, and C** are correct.