Problem 73 - A Complete Resource Book in Chemistry for JEE Main

Question

Glucose reacts with bromine water to produce (a) glyceraldehyde (b) gluconic acid (c) saccharic acid (d) glutaric acid

Step-by-Step Solution

Answer

The product is gluconic acid (b).

Step 1: Recognize the type of reaction with bromine water

When glucose reacts with bromine water, it undergoes an oxidation reaction. Bromine water is an effective reagent for the oxidation of aldehydes in glucose.

Step 2: Determine the reaction outcome

In the presence of bromine water, the aldehyde group at the C1 position in glucose is oxidized to a carboxylic acid group. This transforms glucose into gluconic acid.

Step 3: Conclusion

Considering the oxidation process where the aldehyde group in glucose is oxidized to a carboxylic acid, the product of the reaction is gluconic acid.

Key Concepts

Bromine Water Reactions

Bromine water is a solution of bromine in water that acts as a mild oxidizing agent. In chemical reactions, it is commonly used to test for unsaturation and to oxidize various functional groups. When it reacts with substances, you often see a distinct color change as the brownish color of bromine fades, indicating that a reaction has taken place. In the context of glucose, bromine water targets the aldehyde group, leading to an oxidation reaction. This is a key reaction in organic chemistry because it showcases how specific groups are selectively oxidized, leaving others like the alcohol groups in glucose untouched.

Aldehyde Oxidation

Aldehyde oxidation is a fundamental reaction in organic chemistry where an aldehyde group, characterized by a carbonyl group bonded to a hydrogen atom, is converted into a carboxylic acid. This transformation occurs through the addition of an oxygen atom to the carbonyl group. In the presence of an oxidizing agent like bromine water, the aldehyde group within a compound, such as glucose, undergoes this oxidation process. This is an important transformation because it alters the chemical properties of the molecule, making it more polar and introducing an acidic functional group.

• The aldehyde in glucose specifically refers to the group at the C1 position.
• Its oxidation is essential for converting glucose to gluconic acid.

Glucose Oxidation

Glucose oxidation involves the oxidation of the aldehyde group found at the C1 carbon in the glucose molecule. This process is pivotal in various biochemical and industrial applications. When bromine water is used as the oxidizing agent, it facilitates this specific oxidation without affecting other parts of the glucose molecule.

• The process is selective to the aldehyde.
• It results in the conversion into gluconic acid.

The reaction is a prime example of how specific functional groups within a larger molecule can be selectively targeted by reagents in a controlled reaction.

Gluconic Acid Formation

Gluconic acid is formed when the aldehyde group in glucose is oxidized. This process, specifically using bromine water as an oxidizing agent, is a great demonstration of selective oxidation in organic chemistry. As bromine water oxidizes the aldehyde group at the C1 position, it transforms it into a carboxylic acid group, giving rise to gluconic acid. Gluconic acid itself is useful in various applications due to its acidic properties and its capability to chelate metals.

• This reaction showcase's glucose's versatility in being transformed into more reactive and useful forms.
• The formation of gluconic acid underlines important principles in both academic and applied chemistry fields.