Problem 80 - A Complete Resource Book in Chemistry for JEE Main

Question

Sugarcane on reaction with nitric acid gives (a) \(2 \mathrm{HCOOH}\) (two moles) (b) \(\mathrm{CO}_{2}\) and \(\mathrm{SO}_{2}\) (c) no reaction (d) \((\mathrm{COOH})_{2}\)

Step-by-Step Solution

Answer

(d) \((\mathrm{COOH})_2\) is formed.

Step 1: Identify the Main Components in Sugarcane

Sugarcane primarily contains sucrose, which can be represented as a carbohydrate with the formula \(C_{12}H_{22}O_{11}\). This is a complex sugar molecule.

Step 2: Understand the Nature of Nitric Acid

Nitric acid \(HNO_3\) is a strong oxidizing agent, meaning it can break down complex organic molecules by oxidizing them.

Step 3: Determine the Reaction

As nitric acid is an oxidizing agent, it can oxidize sucrose found in sugarcane to form products like oxalic acid \((COOH)_2\), particularly in the presence of strong acids or bases as catalysts.

Step 4: Analyze Possible Products

Given the options and the chemical behavior of sucrose with an oxidizing agent like nitric acid, the most likely outcome is the formation of oxalic acid \((COOH)_2\). The other products either do not fit the reaction profile or are less likely to form under normal conditions.

Key Concepts

Sucrose Oxidation

When sucrose, a disaccharide sugar found in plants, undergoes oxidation, its chemical structure is altered. The primary formula for sucrose is \(C_{12}H_{22}O_{11}\).
During oxidation, sucrose's complex ring structures are broken down into smaller compounds. Oxidizing agents like nitric acid \(HNO_3\) facilitate this process by adding oxygen to the molecule or removing hydrogen from it. This change makes the sugar molecule more reactive and ready for further reactions.

• Sucrose oxidation typically involves breaking the glycosidic bonds that join glucose and fructose units.
• In an experimental setting, such reactions are often assisted by catalysts that speed up the process.

Through oxidation, we can obtain various products, such as different types of acids. The process is used extensively in industrial applications and chemical research.

Nitric Acid Reactions

Nitric acid \(HNO_3\) is renowned for its powerful oxidizing capabilities, making it a key player in chemical reactions. Particularly when it interacts with organic compounds like sugars, it can cause significant structural changes.
When exposed to organic substrates, nitric acid can convert them into simpler molecules by introducing oxygen or removing electrons. Here's how it generally works:

• The nitrate ion \(NO_3^-\) from \(HNO_3\) acts as the primary oxidizing agent.
• During the reaction, this ion helps break down complex organic molecules, often resulting in the formation of smaller, acidic compounds.

This process is essential in many chemical industries, where nitric acid is used to produce various products, including explosives and fertilizers. Moreover, understanding these reactions allows chemists to manipulate complex organic materials successfully.

Oxalic Acid Formation

Oxalic acid \((COOH)_2\) is among the simplest organic acids formed from the oxidation of organic compounds. In the reaction of sucrose and nitric acid, oxalic acid formation is a typical result due to this acid's stability and simplicity.
When nitric acid oxidizes sucrose, it initiates processes that lead to the breakage of carbon-carbon bonds, resulting in smaller and highly oxidative products, like oxalic acid.

• Oxalic acid has two carboxylic acid groups \((COOH)\).
• Its formula represents its potential to form strong hydrogen bonds, making it crystallize easily.

This compound is prevalent in various applications, from cleaning agents to potential pharmaceuticals. Additionally, identifying oxalic acid as a product of sucrose oxidation underscores the practical ways chemical transformations are harnessed for commercial use.