Which of the following is not oxidized by aqueous `Br_2` ?

Options

A. D - fructose and D - ribulose
B. D - galactose and D - erythrulose
C. D - mannose and d - fructose
D. D - glucose and d - ribose

Answer

To determine which of the following compounds is not oxidized by aqueous Br2, we need to analyze the structures of the given compounds and identify the presence of functional groups that can be oxidized. Aqueous Br2 is known to oxidize aldehydes and certain alcohols.

### Step-by-Step Solution:

1. **Identify the Compounds**: The compounds we need to analyze are:
- D-Fructose
- D-Ribulose
- D-Galactose
- D-Erythrose
- D-Mannose
- D-Glucose
- D-Ribose

2. **Analyze D-Fructose**:
- Structure: D-Fructose has a ketone group (C=O) and does not have an aldehyde group (CHO).
- Conclusion: D-Fructose is not oxidized by aqueous Br2.

3. **Analyze D-Ribulose**:
- Structure: D-Ribulose also has a ketone group and lacks an aldehyde group.
- Conclusion: D-Ribulose is not oxidized by aqueous Br2.

4. **Analyze D-Galactose**:
- Structure: D-Galactose has an aldehyde group (CHO).
- Conclusion: D-Galactose is oxidized by aqueous Br2.

5. **Analyze D-Erythrose**:
- Structure: D-Erythrose has an aldehyde group (CHO).
- Conclusion: D-Erythrose is oxidized by aqueous Br2.

6. **Analyze D-Mannose**:
- Structure: D-Mannose has an aldehyde group (CHO).
- Conclusion: D-Mannose is oxidized by aqueous Br2.

7. **Analyze D-Glucose**:
- Structure: D-Glucose has an aldehyde group (CHO).
- Conclusion: D-Glucose is oxidized by aqueous Br2.

8. **Analyze D-Ribose**:
- Structure: D-Ribose has an aldehyde group (CHO).
- Conclusion: D-Ribose is oxidized by aqueous Br2.

9. **Final Conclusion**:
- The compounds that are not oxidized by aqueous Br2 are D-Fructose and D-Ribulose. However, since we are looking for the option that is not oxidized, we can conclude that D-Fructose is the correct answer.

### Answer:
**D-Fructose is not oxidized by aqueous Br2.**