Which of the following statements is not correct ?

Options

A. Cu liberates `H_2` atom acid
B. In its higher oxidation states , Mn forms stable compounds with oxygen and fluorine
C. `Mn^(3+) and Co^(+)` are oxidising agents in aqueous solution
D. `Ti^(2+) and Cr^(2+)` are reducing agents in aqueous solution

Answer

To solve the question, we need to evaluate each statement provided in the options and determine which one is not correct.

### Step-by-Step Solution:

1. **Evaluate Statement 1**: "Copper liberates hydrogen atom from acid."
- **Analysis**: Copper (Cu) is below hydrogen in the electrochemical series, which means it cannot displace hydrogen from acids. Therefore, this statement is incorrect.

2. **Evaluate Statement 2**: "In its higher oxidation state, Mn forms stable compounds with oxygen and fluorine."
- **Analysis**: Manganese can exist in multiple oxidation states, including +7. In this state, it can form stable compounds with highly electronegative elements like oxygen and fluorine. This statement is correct.

3. **Evaluate Statement 3**: "Mn^3+ and Co^1+ are oxidizing agents in aqueous solution."
- **Analysis**: An oxidizing agent is a substance that gains electrons and is reduced in the process. Mn^3+ can accept an electron to become Mn^2+, and Co^1+ can also accept an electron. Thus, this statement is correct.

4. **Evaluate Statement 4**: "Ti^2+ and Cr^2+ are reducing agents in aqueous solution."
- **Analysis**: Reducing agents lose electrons and are oxidized in the process. Ti^2+ and Cr^2+ can lose electrons to form Ti^3+ and Cr^3+, respectively. Therefore, this statement is also correct.

### Conclusion:
Based on the evaluations:
- Statement 1 is incorrect.
- Statements 2, 3, and 4 are correct.

Thus, the answer to the question "Which of the following statements is not correct?" is **Option 1**.

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