The reagent used in Ruff's degradation is :

Options

A. Bayer's reagent
B. Tollen's reagent
C. Fenton reagent
D. Benedict's reagent

Answer

To answer the question regarding the reagent used in Ruff's degradation, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Ruff's Degradation**: Ruff's degradation is a chemical reaction that involves the conversion of aldoses (like D-glucose) into aldoses with one less carbon atom (like D-arabinose).

2. **Identifying the Reactants**: In the case of D-glucose, the reaction typically involves bromine water and calcium hydroxide. This combination helps in the formation of an intermediate compound.

3. **Formation of Intermediate**: The reaction of D-glucose with bromine water and calcium hydroxide leads to the formation of a specific intermediate that contains a carboxylate group (C=O) and a calcium ion (Ca²⁺).

4. **Adding the Reagent**: The next step in Ruff's degradation involves adding a reagent that will facilitate the conversion of the intermediate into the final product, D-arabinose.

5. **Identifying the Reagent**: The reagent used in this step is known as the "Phantone reagent." This can be represented by compounds such as:
- Ferric chloride (FeCl₃) in H₂O₂ (30% solution)
- Ferric acetate (Fe(OAc)₃) in H₂O₂ (30% solution)

6. **Final Product**: The reaction ultimately yields D-arabinose, which has one less carbon than D-glucose.

7. **Conclusion**: Therefore, the reagent used in Ruff's degradation is the Phantone reagent.

### Final Answer:
The reagent used in Ruff's degradation is **Phantone reagent**.