A well known reagent which contains copper sulphate, sodium potassium tartarate and sodium hydroxidc is :

Options

A. Fenton's reagent
B. Schiff's reagent
C. Fehling's solution
D. Nessler's reagent

Explanation

To solve the question about the well-known reagent that contains copper sulfate, sodium potassium tartrate, and sodium hydroxide, we can follow these steps:

### Step 1: Identify the Components
The question mentions three components:
- Copper sulfate (CuSO₄)
- Sodium potassium tartrate (C₄H₄NaKO₆)
- Sodium hydroxide (NaOH)

### Step 2: Recognize the Reagent
The combination of these three components is known as "Fehling's solution." Fehling's solution is used to test for the presence of reducing sugars and aldehydes.

### Step 3: Understand the Purpose of the Reagent
Fehling's solution is specifically used to detect the presence of aldehydes, particularly in the identification of reducing sugars. When a reducing sugar is present, it will reduce the copper(II) ions in the copper sulfate to copper(I) oxide, which precipitates as a red solid.

### Step 4: Conclusion
Thus, the well-known reagent that contains copper sulfate, sodium potassium tartrate, and sodium hydroxide is **Fehling's solution**.

### Final Answer
The well-known reagent is **Fehling's solution**.

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