Problem 76 - A Complete Resource Book in Chemistry for JEE Main

Question

The process, which is catalysed by one of the products, is called (a) acid base catalysis (b) negative catalysis (c) positive catalysis (d) auto catalysis

Step-by-Step Solution

Answer

The process is called auto catalysis.

Step 1: Understand the Definition of Catalysis

To solve the exercise, you need to understand that catalysis involves a reaction in which the rate is increased by a material called a catalyst. A catalyst is not consumed in the reaction and can be reused.

Step 2: Identify Types of Catalysis

You should be familiar with different types of catalysis: 1. Acid-base catalysis involves transfer of protons. 2. Negative catalysis slows down a reaction. 3. Positive catalysis speeds up a reaction. 4. Auto-catalysis occurs when one of the products of the reaction acts as a catalyst.

Step 3: Apply Definition to Options

Look at the options and apply the definitions. The process described is catalyzed by one of its products, which matches the description of auto-catalysis.

Step 4: Select the Correct Answer

Based on the definitions and the process described in the exercise, the answer is 'auto catalysis' because the reaction is catalyzed by one of its own products.

Key Concepts

Types of Catalysis

Catalysis is a fascinating phenomenon in chemistry where the rate of a chemical reaction is modified by a substance known as a catalyst. Let's explore the types of catalysis you might encounter:

• Acid-Base Catalysis: This type involves the transfer of protons (H⁺) between the chemicals involved. It can either donate or accept protons, which helps in the reaction pathway.
• Negative Catalysis: Contrary to most catalysis types, it decreases the reaction rate. Also known as inhibition, it occurs when a substance makes a reaction occur slower than it normally would.
• Positive Catalysis: This speeds up reactions by lowering the activation energy required for the reaction. Most catalysts fall into this category, as they facilitate faster and more efficient chemical reactions.
• Auto-Catalysis: A unique and intriguing type, where one of the products of the reaction itself acts as the catalyst. This can often lead to self-sustaining reactions, because as the reaction progresses, more catalyst is produced.

These categories help chemists understand and predict reaction behaviors and design specific catalysts for desired reactions.

Catalyst Role in Reactions

Catalysts play a crucial role in chemical reactions. Their primary function is to alter the rate of the reaction without being consumed in the process. When a catalyst is present, it provides an alternative pathway for the reaction, typically with lower activation energy than the un-catalyzed pathway.

• They allow reactions to occur more quickly and under less extreme conditions, which can be useful for industrial applications.
• Catalysts can be homogeneous (in the same phase as the reactants) or heterogeneous (in a different phase).

A fascinating aspect of catalysts is their ability to be specific. Specificity allows them to affect only specific reactions or paths, ensuring targeted modifications in complex chemical systems. Moreover, they remain unchanged after the reaction, ready to assist in multiple cycles of the same reaction.

Reaction Rate Analysis

Analyzing reaction rates is a fundamental part of understanding chemical kinetics. Several factors can influence how quickly reactions proceed:

• Concentration of Reactants: Generally, the higher the concentration of the reactants, the faster the reaction rate.
• Temperature: Increasing temperature usually leads to faster reactions because it raises kinetic energy, leading to more collisions among reacting molecules.
• Presence of a Catalyst: As mentioned, catalysts lower the activation energy required, which increases the reaction rate.

For chemical engineers and scientists, measuring and studying these rates allow the optimization of conditions to maximize product yield. Reaction rate analysis involves determining the speed at which reactants turn into products, which helps in predicting how long a reaction will take. This can be achieved through various techniques, like monitoring concentration changes over time.