Question

This section contains multiple choice questions. Each question has 4 choices (a), (b), (c) and (d), out of which ONLY ONE is correct. The products of oxidation of glucose by bromine water and conc.HNO, are respectively (a) gluconic acid and glucaric acid (b) oxalic acid and saccharic acid (c) glucaric acid and gluconic acid (d) saccharic acid and oxalic acid

Short answer

Answer: Gluconic acid and saccharic acid.

Step-by-step solution

Oxidation of glucose by bromine water

Bromine water acts as a mild oxidizing agent. When glucose is exposed to bromine water, the aldehyde group is selectively oxidized, forming gluconic acid as the product.

Oxidation of glucose by concentrated HNO₃

Concentrated nitric acid (HNO₃) is a strong oxidizing agent. When glucose undergoes oxidation by HNO₃, both the aldehyde group and primary alcohol group get oxidized, forming saccharic acid as the product.

Identify the correct option

Now that we know the products of both reactions, we can identify the correct option. From our analysis, oxidation of glucose by bromine water results in gluconic acid, and oxidation of glucose by concentrated HNO₃ results in saccharic acid. So, the correct answer is option (a).

Key concepts

Bromine Water

Bromine water is a solution of bromine in water, often used as a mild oxidizing agent in organic chemistry. This reagent has a distinct reddish-brown color due to the bromine. When used in reactions, it is particularly useful for selectively oxidizing certain functional groups.
In the context of glucose oxidation, bromine water can oxidize the aldehyde group at the end of the glucose molecule.

• Selective oxidation: Bromine water specifically targets the aldehyde group.
• Reactions are usually performed at room temperature.
• The product of this oxidation is gluconic acid, which is a less harsh transformation compared to stronger oxidants.

This selective nature adds value to bromine water as it helps chemists modify the structure of organic compounds precisely.

Gluconic Acid

Gluconic acid is an organic compound resulting from the mild oxidation of glucose. In this process, only the aldehyde group at the C1 position is affected, converting it into a carboxylic acid group.
This transformation maintains the sugar's basic structure while altering its properties.

• Gluconic acid has a sour taste and is not as soluble as glucose.
• It occurs naturally in fruit, honey, and wine, as well as being used commercially.
• It's often used in the food industry as a food additive, preservative, and a component in cleaning products.

Gluconic acid’s role extends to its application in various industries, making it a compound of significant importance beyond just its chemical synthesis.

Concentrated Nitric Acid

Concentrated nitric acid (HNO₃) is a powerful oxidizing agent, recognized by its pungent fume and molecular composition, making it highly effective in strong oxidation reactions. Unlike bromine water, nitric acid affects more than just the aldehyde group in glucose.

• It oxidizes both the aldehyde group and the primary alcohol group found in glucose.
• The process is more vigorous, transforming glucose entirely into saccharic acid.
• Handling requires caution due to its corrosive nature and ability to cause burns.

This strength makes concentrated nitric acid a versatile reagent in oxidizing alcohols and aldehydes, contributing to the synthesis of various acids, including saccharic acid.

Saccharic Acid

Saccharic acid, also known as glucaric acid, is the product of the complete oxidation of glucose. Through the action of strong oxidizing agents like concentrated nitric acid, both the aldehyde group and the primary alcohol group in glucose are oxidized to carboxylic acids.

• This results in a dicarboxylic acid, saccharic acid, which has enhanced stability and different properties compared to glucose.
• Saccharic acid is used in diverse applications such as water treatment processes and the creation of biodegradable polymers.
• Its structure provides rigidity and resistance to chemicals, making it valuable in various manufacturing industries.

Understanding saccharic acid’s formation and stability has opened up paths for innovations in environmental and industrial applications, highlighting its broader significance in chemistry.