Problem 143 - A Complete Resource Book in Chemistry for JEE Main

Question

Fructose on oxidation with conc. HNO \(_{3}\) gives (a) Tartaric acid (b) Saccharic acid (c) Glycolic acid (d) Both (a) and (c)

Step-by-Step Solution

Answer

The oxidation of fructose with conc. HNO\(_{3}\) gives saccharic acid, option (b).

Step 1: Understanding the Reaction Type

The exercise involves the oxidation of fructose using concentrated nitric acid (HNO\(_{3}\)). When sugars such as fructose are oxidized with strong oxidizing agents like HNO\(_{3}\), they typically form specific dicarboxylic acids.

Step 2: Identifying The Product of Fructose Oxidation

In organic chemistry, fructose on oxidation with concentrated HNO\(_{3}\) yields saccharic acid. This is due to the oxidative cleavage of its primary alcohol groups into carboxylic acids.

Step 3: Checking the Options

From the given options, we need to find which compound matches the oxidation product of fructose. The product, saccharic acid, corresponds to option (b).

Key Concepts

Saccharic Acid

Saccharic acid, also known as glucaric acid, is a dicarboxylic acid produced during the oxidation of sugars such as glucose and fructose. It is uniquely characterized by having two carboxyl groups at opposite ends of its molecular structure. This results from the transformation of the alcohol groups present in the sugar into carboxyl groups. Saccharic acid is an essential compound in organic chemistry due to its potential applications, such as being a precursor for biodegradable polymers. Understanding its formation through oxidation helps in grasping important concepts of sugar chemistry and how alcohol groups can be converted to other functional groups. Moreover, saccharic acid contributes significantly to studying carbohydrate metabolism and conversions, especially in understanding the oxidative breakdown of carbohydrates. By delving into the process by which fructose transforms into saccharic acid, you also become familiar with broader themes within organic reactions such as oxidative cleavage and functional group interconversion.

Concentrated Nitric Acid

Concentrated nitric acid ( HNO _{3} ) is a powerful oxidizing agent widely used in organic chemistry reactions, particularly for oxidizing alcohols to carboxylic acids. Its effectiveness lies in its ability to facilitate the breaking of carbon-hydrogen (C-H) bonds in alcohols and convert them to carbon-oxygen (C=O) bonds found in carboxylic acids. In the context of sugar oxidation, like with fructose, concentrated nitric acid serves to convert the primary alcohol groups of a sugar into carboxyl groups, forming a dicarboxylic acid, such as saccharic acid. The reaction involves the oxidative cleavage of sugar rings, which not only breaks down the sugar but also provides products of significant value and functionality. Understanding how concentrated nitric acid achieves these conversions is crucial for comprehending how complex, multi-functional molecules can be simplified and restructured via oxidation, revealing underlying reactivity inside organic compounds.

Organic Chemistry Reactions

Organic chemistry reactions include diverse processes where substances transform into different compounds. These reactions are vital for creating new materials, energy sources, and pharmaceuticals. Among these processes, oxidation reactions are prominent in transforming alcohol-containing molecules into more functional molecules like carboxylic acids. With sugars like fructose, oxidation using agents such as concentrated nitric acid leads to the formation of complex acids like saccharic acid. Key points in organic reactions:

• They involve the transformation of functional groups.
• Oxidation reactions often turn alcohol groups into carboxyl groups.
• Understanding these transformations is essential for predicting product outcomes in organic reactions.

Mastering organic chemistry requires understanding the types of reactions and the potential transformations each reactant can undergo. Oxidation reactions of sugars offer a practical example of how organic substances are manipulated to produce functional and high-value compounds.