Problem 29 - Arihant Objective Approach to Organic Chemistry for IIT JEE and NEET all Medical Entrances Part 4

Question

Sucrose on treatment with \(\mathrm{HCl}\) produces: (a) glucose (b) fructose (c) both (a) and (b) (d) laevulinic acid

Step-by-Step Solution

Answer

Sucrose with HCl produces both glucose and fructose. Option (c) is correct.

Step 1: Understanding the Reaction

Sucrose is a disaccharide composed of glucose and fructose. When it is treated with hydrochloric acid (HCl), it undergoes a hydrolysis reaction.

Step 2: Hydrolysis Explanation

Hydrolysis is a chemical reaction in which water is used to break bonds. In this case, HCl acts as a catalyst to help water split sucrose into its two monosaccharide components.

Step 3: Identify the Products

Upon hydrolysis, sucrose splits into glucose and fructose. This is because the glycosidic bond linking glucose and fructose is broken.

Step 4: Choose the Correct Option

Since sucrose hydrolyzes into both glucose and fructose, the correct answer is option (c): both (a) and (b).

Key Concepts

Glucose

Glucose is a simple sugar, also known as a monosaccharide, which plays a crucial role in biology as a primary source of energy. It is a carbohydrate, which means it is composed of carbon (C), hydrogen (H), and oxygen (O) atoms. The chemical formula for glucose is \(C_6H_{12}O_6\). It is one of the most important carbohydrates as it is used by almost all living organisms for cellular respiration.

• Glucose provides energy that cells need to perform activities and functions efficiently.
• It is commonly stored as glycogen in the liver and muscles for future energy needs.
• Being a building block of more complex carbohydrates, it is crucial in the synthesis of molecules such as sucrose and starch.

The structure of glucose is such that it can easily ring-form in aqueous solutions, which makes it versatile in biochemical reactions. Moreover, it is easily transported in the bloodstream, ensuring rapid distribution to all body cells.

Fructose

Fructose is another simple sugar and monosaccharide, just like glucose, but it has a different structure and properties. Its chemical formula is also \(C_6H_{12}O_6\), similar to glucose, but the molecular arrangement is distinct. This structural difference grants fructose unique characteristics compared to glucose.

• Fructose is found naturally in fruits, honey, and root vegetables, giving them their sweet flavor.
• It is metabolized differently than glucose, primarily in the liver.
• Fructose is often used in processed foods and beverages as a sweetener, often in the form of high-fructose corn syrup.

In sucrose, fructose is bonded with glucose, contributing to the sweetness of table sugar. Understanding the metabolism of fructose is important, especially with its rising intake in modern diets.

Glycosidic Bond

The glycosidic bond is a type of covalent bond that holds monosaccharides together, forming disaccharides and polysaccharides. In sucrose, this bond connects a glucose molecule to a fructose molecule. It is formed during a dehydration synthesis reaction, where a water molecule is removed as the two monosaccharides bond.

• In the case of sucrose, the bond specifically connects the anomeric carbon of glucose to the anomeric carbon of fructose.
• The bond plays a key role in hydrolysis reactions, as breaking it releases free glucose and fructose molecules.
• Enzymes such as sucrase are involved in the catalysis of breaking these bonds efficiently in biological systems.

Understanding glycosidic bonds is pivotal in studying carbohydrate digestion and synthesis, as they dictate how sugars are formed and metabolized in the body.