What product or products are obtained when D-galactose reacts with each of the following?
e. Br₂ in water

Verified step by step guidance

1. Identify the functional groups present in d-galactose. D-galactose is an aldose sugar, meaning it contains an aldehyde group (-CHO) at the anomeric carbon (C1) and hydroxyl groups (-OH) on the other carbons.
2. Understand the reactivity of Br2 in water. Bromine in water is a mild oxidizing agent that selectively oxidizes aldehydes to carboxylic acids without affecting other functional groups like alcohols.
3. Focus on the aldehyde group in d-galactose. The aldehyde group at C1 will be oxidized to a carboxylic acid group (-COOH), converting d-galactose into d-galactonic acid.
4. Note that the hydroxyl groups on the other carbons of d-galactose remain unchanged during this reaction because Br2 in water does not oxidize alcohols under these conditions.
5. Conclude that the product of the reaction is d-galactonic acid, which is the oxidized form of d-galactose where the aldehyde group has been converted to a carboxylic acid group.

Key Concepts

Oxidation of Sugars

The reaction of sugars like d-galactose with oxidizing agents, such as Br2 in water, leads to the oxidation of the hydroxyl groups. This process can convert the aldehyde or alcohol functional groups into carboxylic acids or other oxidized forms, depending on the conditions and the specific sugar structure.

D-Galactose Structure

D-galactose is a six-carbon aldose sugar with a specific stereochemistry. Understanding its structure, including the arrangement of hydroxyl groups and the aldehyde functional group, is crucial for predicting the products of its reactions, particularly how it interacts with oxidizing agents.

Halogenation Reactions

Halogenation involves the introduction of halogen atoms into organic compounds. In the case of d-galactose reacting with Br2 in water, the reaction can lead to the formation of brominated products, which may include oxidized forms of the sugar, highlighting the importance of understanding reaction mechanisms in organic chemistry.