Fehling A and Fehling B are :

Options

A. `CuSO_(4)` solution and `NH_(4)OH` solution
B. `CuSO_(4)` solution and alkaline soluton of sodium potassium tartarate
C. `CuSO_(4)` solution and alkaline solution ofsodium citrate
D. `CuSO_(4)` solution and `NaOH` solution.

Explanation

### Step-by-Step Text Solution:

1. **Understanding Fehling's Solutions**: Fehling's solutions consist of two separate solutions, known as Fehling's A and Fehling's B, which are mixed together before use.

2. **Fehling's A**:
- Fehling's A is an aqueous solution of copper(II) sulfate (CuSO₄).
- It is typically a blue solution due to the presence of copper ions.

3. **Fehling's B**:
- Fehling's B is an alkaline solution made by dissolving sodium potassium tartrate (also known as Rochelle salt) in water, along with sodium hydroxide (NaOH) to maintain the alkaline environment.
- This solution is responsible for providing the necessary basic conditions for the reaction.

4. **Purpose of Fehling's Solutions**:
- Fehling's solutions are primarily used to test for the presence of aldehydes.
- Aldehydes can reduce the copper(II) ions in Fehling's A to copper(I) oxide (Cu₂O), which precipitates as a red solid, indicating a positive test.

5. **Conclusion**:
- In summary, Fehling's A is copper sulfate solution, and Fehling's B is an alkaline solution of sodium potassium tartrate.
- Therefore, the correct identification of Fehling's A and B is:
- Fehling's A: Copper sulfate solution
- Fehling's B: Alkaline solution of sodium potassium tartrate (Rochelle salt)

### Final Answer:
Fehling's A is copper sulfate solution, and Fehling's B is an alkaline solution of sodium potassium tartrate.

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