Class 12 Chemistry - HARYANA
Chemical Kinetics
Chemical Kinetics is a crucial branch of physical chemistry dealing with the rates of chemical reactions, the factors affecting them, and the mechanisms by which they occur. For Class 12 Haryana (BSEH) board exams, this chapter is high-scoring and forms a major part of numerical and theoretical questions. Students will learn about reaction rates, rate laws, order and molecularity of reactions, integrated rate equations for zero and first-order reactions, and the effect of temperature on reaction rates using the Arrhenius equation.
Start Learning FreeKey Concepts
Rate of Reaction
The change in concentration of a reactant or product in a given unit of time.
Rate Law and Rate Constant
An expression that relates the rate of a reaction to the concentration terms of reactants, where the proportionality constant is the rate constant.
Order of Reaction
The sum of the powers of the concentrations of the reactants in the rate law expression, which can be zero, fractional, or integer.
Molecularity
The number of reacting species colliding simultaneously in an elementary reaction; it is always a whole number and cannot be zero.
Arrhenius Equation
An equation that expresses the quantitative relationship between the rate constant and temperature, incorporating activation energy.
Important Formulas
Board Exam Info
In the Haryana (BSEH) Class 12 Chemistry board exam, Chemical Kinetics typically carries around 4 to 6 marks. Expect a mix of 1-mark objective questions, conceptual reasoning questions about molecularity and order, and a compulsory numerical problem based on first-order half-life or the Arrhenius equation.
Frequently Asked Questions
What is the difference between order and molecularity?
Order is an experimental quantity representing the sum of concentration powers in the rate law, whereas molecularity is a theoretical concept representing the number of colliding species in an elementary step.
Can the order of a reaction be zero or fractional?
Yes, order can be zero, fractional, or even negative. However, molecularity is always a whole number between 1 and 3.
What is activation energy?
It is the minimum extra amount of energy absorbed by reactant molecules so that their energy equals threshold energy and they can undergo a chemical reaction.
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