Which reagent gives pink colour with aldehyde ?

Options

A. Tollen's reagent
B. Schiff reagent
C. Fehling solution
D. Benedict solution

Answer

To determine which reagent gives a pink color with aldehydes, we can analyze the reactions that occur with different reagents.

### Step-by-Step Solution:

1. **Understanding Aldehydes**:
Aldehydes are organic compounds containing a carbonyl group (C=O) with at least one hydrogen atom attached to the carbon. They are known to be reducing agents.

2. **Identifying Reagents**:
We need to identify reagents that react with aldehydes and produce a pink color. Common reagents used for testing aldehydes include Tollens' reagent, Fehling's solution, and Benedict's solution.

3. **Tollens' Test**:
Tollens' reagent (silver ammonium solution) is used to test for aldehydes. When an aldehyde reacts with Tollens' reagent, it reduces silver ions (Ag+) to metallic silver, forming a silver mirror. This test does not produce a pink color.

4. **Fehling's Test**:
Fehling's solution consists of two parts: Fehling A (copper(II) sulfate) and Fehling B (sodium potassium tartrate and sodium hydroxide). When an aldehyde is added, it reduces Cu²⁺ to Cu₂O, which precipitates as a reddish-brown solid. This is also not a pink color.

5. **Benedict's Test**:
Similar to Fehling's test, Benedict's reagent contains copper(II) sulfate and sodium carbonate. When an aldehyde is present, it reduces the copper ions, resulting in a color change that can range from green to red, depending on the amount of reducing sugar present. However, it does not specifically yield a pink color.

6. **Siebeneich's Test**:
The reagent that gives a pink color with aldehydes is the Siebener test, which involves the reaction of aldehydes with certain amines. When an aldehyde reacts with an amine, a compound is formed that can exhibit a pink color.

7. **Conclusion**:
The reagent that gives a pink color with aldehydes is the one used in the Siebener test.

### Final Answer:
The reagent that gives a pink color with aldehyde is **Siebeneich's reagent**.

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