`D`-Glucose and `D`-fructose both form the same osazone, Which statements are correct about the above reaciton?

Options

A. Glucose and fructose are epimers.
B. Glucose and fruc tose are anomers.
C. The c onfigurations of the OH group at C-3 and c-4 in glucose and fruc tose are same.
D. The configurations of the OH group at C -4 and C-5 in glucose and fructose are same.

Answer

To determine which statements are correct regarding the reaction between D-glucose and D-fructose that leads to the formation of the same osazone, we will analyze the structures and properties of both sugars.

### Step-by-Step Solution:

1. **Identify the Structures of D-Glucose and D-Fructose**:
- D-Glucose is an aldohexose, meaning it contains an aldehyde group (-CHO) at the first carbon.
- D-Fructose is a ketohexose, meaning it contains a ketone group (C=O) at the second carbon.

2. **Understand the Concept of Osazone Formation**:
- Osazones are formed when sugars react with phenylhydrazine. Both D-glucose and D-fructose can react with phenylhydrazine to form the same osazone due to their structural similarities in the cyclic forms.

3. **Examine the Statements**:
- **Statement 1**: "Glucose and fructose are epimers."
- **Analysis**: This statement is incorrect. Epimers are sugars that differ at only one chiral center. Since glucose and fructose differ at more than one chiral center, they are not epimers.

- **Statement 2**: "Glucose and fructose are anomers."
- **Analysis**: This statement is also incorrect. Anomers differ at the anomeric carbon (the carbon that becomes chiral upon ring closure). Since glucose and fructose do not have the same anomeric carbon, they cannot be anomers.

- **Statement 3**: "The configuration of the OH group at C3 and C4 in glucose and fructose is the same."
- **Analysis**: This statement is correct. Both sugars have the same configuration at these positions, which contributes to their ability to form the same osazone.

- **Statement 4**: "The configuration of the OH group at C4 and C5 in glucose and fructose is the same."
- **Analysis**: This statement is also correct. The configurations at these positions are the same in both sugars.

4. **Conclusion**:
- The correct statements regarding the reaction of D-glucose and D-fructose forming the same osazone are:
- Statement 3 is correct.
- Statement 4 is correct.

### Final Answer:
- The correct statements about the reaction are:
- Statement 3 and Statement 4 are correct.