The reagent which forms crystalline osazone derivatives when heated with glucose is?

Options

A. Fehling solution
B. Phenylhydrazine
C. Benedicts solution
D. Hydroxylamine

Answer

To solve the question regarding the reagent that forms crystalline osazone derivatives when heated with glucose, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Osazone Formation**:
- Osazones are formed when reducing sugars react with phenylhydrazine. This reaction involves the formation of a hydrazone followed by rearrangement to form the osazone.

2. **Identifying the Reagent**:
- The reagent that reacts with glucose to form osazone is phenylhydrazine. The chemical formula for phenylhydrazine is C6H5NHNH2.

3. **Reaction with Glucose**:
- Glucose, which is an aldose sugar, contains an aldehyde group. When glucose is mixed with phenylhydrazine and heated, the aldehyde group of glucose reacts with phenylhydrazine.

4. **Formation of Glucosazone**:
- The reaction leads to the formation of a crystalline product known as glucosazone. This product is characterized by the presence of the phenylhydrazone structure.

5. **Conclusion**:
- Therefore, the reagent that forms crystalline osazone derivatives when heated with glucose is **phenylhydrazine**.

### Final Answer:
The reagent which forms crystalline osazone derivatives when heated with glucose is **phenylhydrazine**.

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