Question

Write the reaction of bromine water on glucose.

Hint:

Bromine water is "mild". If a strong oxidizing agent like conc. \( HNO_3 \) were used, both the aldehyde and the primary alcohol group would be oxidized to form saccharic acid.

Answer 1

Step 1: Understanding the Concept:
Bromine water ($Br_2/H_2O$) is a mild oxidizing agent. It specifically oxidizes the aldehyde group ($-CHO$) of glucose without affecting the hydroxyl groups.
Step 2: Detailed Explanation:
Glucose contains one aldehyde group and five hydroxyl groups. When treated with bromine water, the aldehyde group is oxidized to a carboxylic acid group ($-COOH$).
The product formed is gluconic acid.
Reaction:
\[ CHO-(CHOH)_4-CH_2OH \xrightarrow{Br_2/H_2O} COOH-(CHOH)_4-CH_2OH \]
This reaction confirms the presence of an aldehyde group in the open-chain structure of glucose.
Step 3: Final Answer:
Glucose reacts with bromine water to form gluconic acid.