Fructose reduces Tollens reagent due to

Options

A. Presence of ketonic group
B. Presence of `NH_(4)OH` is Tollen's reagent
C. Rearrangement of fructose into a -mixture of glucose, fructose and mannose
D. Both (2) & (3)

Answer

**Step-by-Step Solution:**

1. **Identify the Nature of Fructose**:
Fructose is a simple sugar (monosaccharide) that is classified as a ketose because it contains a ketone functional group.

2. **Understanding Tollens' Reagent**:
Tollens' reagent is a chemical reagent used to test for the presence of aldehydes. It contains silver nitrate in ammonia and is known to oxidize aldehydes to carboxylic acids while being reduced itself, resulting in a silver mirror.

3. **Aldehydes vs. Ketones**:
Aldehydes are easily oxidized and can reduce Tollens' reagent, while ketones generally do not oxidize easily. However, certain conditions can allow some ketones to behave like aldehydes.

4. **Enolization of Fructose**:
In an aqueous solution, fructose can undergo a process called enolization, where it can convert into an enol form. This enol form can tautomerize to an aldehyde.

5. **Reduction of Tollens' Reagent**:
The aldehyde form of fructose can then reduce Tollens' reagent. Therefore, although fructose is a ketone, it can still reduce Tollens' reagent due to its ability to form an aldehyde in solution.

6. **Conclusion**:
Fructose reduces Tollens' reagent because it can enolize and form an aldehyde, which is capable of reducing the reagent. The presence of the ketone group allows for this transformation under specific conditions.

**Final Answer**: Fructose reduces Tollens' reagent due to the presence of a ketone group that can enolize to form an aldehyde.

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