FACTORS AFFECTING RATE OF REACTION:

The rate of a chemical reaction, which measures how quickly reactants are consumed or products are formed, is influenced by several factors. Understanding these factors helps in controlling and optimizing reaction rates. Here are the key factors affecting the rate of a reaction:

1. Nature of Reactants:The chemical nature of the reactants involved in a reaction plays a significant role. Some reactions occur more readily than others due to the inherent reactivity of the substances involved. For example, reactions between highly reactive elements or compounds tend to proceed at faster rates compared to reactions involving less reactive species.
2. Concentration:The concentration of reactants affects the rate of a reaction. Generally, an increase in reactant concentration leads to an increase in the reaction rate. This is because a higher concentration provides more reactant particles, leading to a higher collision frequency and an increased likelihood of successful collisions.
3. Temperature:The rate of reaction increases with the increase in temperature. In most cases, the rate of reaction becomes nearly double for 10⁰ rise in temperature. In some cases, reactions do not take place at room temperature but take place at higher temperatures.
4. Pressure (for gases): In the case of gaseous reactants, pressure can influence the reaction rate, particularly for reactions involving gases. Increasing the pressure of gaseous reactants can enhance the reaction rate by increasing the collision frequency between gas molecules.
5. Surface Area: In reactions involving solid reactants, the surface area of the solid can significantly impact the reaction rate. A larger surface area provides a more exposed area for reactant particles to interact, leading to more collisions and a faster reaction rate. Therefore, finely divided or powdered forms of solids tend to react faster compared to bulky or solid pieces.
6. Catalysts:Catalysts are substances that accelerate a reaction by providing an alternative reaction pathway with lower activation energy. They increase the rate of reaction without being consumed in the process. Catalysts can significantly enhance reaction rates and are widely used in various industrial and biological processes.
7. Presence of Inhibitors: Inhibitors are substances that decrease the rate of a reaction. They work by interfering with the reaction mechanism, reducing the effectiveness of collisions, or inhibiting the formation of active intermediates. Inhibitors are often used to control reaction rates or to prevent unwanted reactions.

Understanding and manipulating these factors allow scientists and engineers to control and optimize reaction rates for various applications, ranging from industrial processes to pharmaceutical synthesis and energy production.

Which of the following statement is false?

Molecularity influences the rate of reaction

The correct answer is option 2. Molecularity influences the rate of reaction.

Let us address the statement regarding molecularity and why it might be considered false:

Statement: Molecularity influences the rate of reaction

Molecularity refers to the number of molecules or ions that participate as reactants in an elementary step of a chemical reaction. It is a concept used in the context of reaction mechanisms, particularly in elementary reactions where reactants directly collide to form products.

In classical reaction kinetics, the rate law (or rate equation) expresses how the rate of a chemical reaction depends on the concentrations of reactants. The rate law for a reaction involving multiple steps is influenced by the order of each reactant in the rate-determining step, not directly by molecularity.

Clarification:

Molecularity does not directly influence the rate of a reaction as expressed in the rate law. Instead, molecularity describes the theoretical mechanism of reaction steps where reactants collide in a specific manner to form products.

Rate-determining step: The rate of a reaction is predominantly determined by the slowest step (rate-determining step) in its mechanism. The rate law is derived from this step and is influenced by the order of reactants in this step, not by the molecularity of the overall reaction mechanism.

Conclusion:

The false statement among the options provided is indeed: Molecularity influences the rate of reaction. This statement is incorrect because molecularity describes the mechanism of reaction steps (number of molecules involved in collision) rather than directly influencing the rate law which depends on the order of reactants in the rate-determining step.