“You can’t cross the sea merely by standing and staring at the water.” – Tagore
Chemical kinetics is the branch of chemistry which deals majorly with the rates of chemical reactions. There are many reactions which occur instantaneously like AgNO_{3} with HCl to form a salt i.e, AgCl while there are many reactions which occur too slow like the conversion of diamond into graphite. Along with feasibility, there are various other factors like rate and other parameters which control the rate of reactions. Chemical kinetics consider into account of all such types of reactions and tell us about their rate and the order of these reactions. In this chapter, you will learn about the rates and order of the reactions, Arrhenius equation, collision theory of reactions, etc.
In everyday life, there are various important chemical reactions which occur around us as follows:
Role of chemical kinetics in the "refrigerator": We keep our food items in the refrigerator because it lowers the temperature of these substances. As the temperature is lowered, the reaction rates are low and thus the food items can be used for longer times.
Role of chemical kinetics in the making of "popcorn": Each popcorn kernel contains little amount of water in them. Now when the popcorn kernels are heated, then the water turns into the vapour which tries to come out of the kernel shell. Due to this heating and vapourisation, as the pressure is further is increased, the kernel shells are burst out with a 'pop' sound.
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In chemical kinetics, you also learn about how on changing the reaction conditions like temperature and pressure, the rate of reaction changes. It also gives you information about the reaction mechanisms, activation energy and reaction intermediates.
In this section, you will study about the important topics of the chapter, overview, formulae and some important tips and guidelines for the preparation of the chapter at the best.
Rate of chemical reaction
Factors influencing the rate of reaction
Order of a reaction
Zeroorder reactions
First order reactions
Second order reactions
Pseudo first order reactions
Arrhenius equation, Activation energy and its determination
Collision theory of reactions
(i) Rate of reaction: Similar to any object moving with a certain velocity, chemical reactions also occur with certain velocities also known as the rate of reaction. This rate of reaction is defined as how fast the product is forming or how fast the reactants are getting consumed with respect to time. Mathematically, it can be expressed as follows:
(ii) Rate expression and rate constant: For the general reaction:
The rate equation is given as follows:
This equation can be written as follows:
where x and y may or may not be stoichiometric coefficients. The addition of these components (x+y) gives the order of the reaction.
(iii) Order of the reaction: The rate equation of a chemical reaction is given as:
where (x+y) gives the order of the reaction and k is the rate constant.
Units of rate constant: For a general reaction:
The unit of rate constant (k) depends on the order of the reaction i.e. (x+y).
Reaction type 
Order of reaction 
Units of rate constant 
Zeroorder reaction 
0 
mol L^{1 }s^{1} 
First order reaction 
1 
s^{1} 
Second order reaction 
2 
mol^{1}L s^{1} 
Zeroorder reaction: It is the type of reaction, where the order of reaction is proportional to the zero power of the concentration of reactants. The rate equation is given as follows:
First order reaction: In these type of reactions, the rate of reaction is proportional to the first power of the concentration of reactants. The rate equation is given as follows:
The halflife of reaction: It is the time at which the concentration of reactant is half of its initial value. It is denoted by t_{1/2}. Mathematically, it can be described as follows:
Arrhenius Equation: The rate of a chemical reaction depends on the temperature. For every 10^{0} rise in temperature, the rate constant gets doubled. This temperature dependency of the rate of chemical reaction is explained by the Arrhenius equation as given below:
k = A e^{Ea/RT}
where A is the Arrhenius factor, E_{a} is the activation energy and R is the gas constant
Collision Theory of Chemical Reactions: This theory gives a deeper insight into the mechanism of the chemical reactions. According to this theory, the reactant molecules are considered to be spherical molecules and the reaction occurs when these spherical molecules collide with each other. Mathematically, it can be described as follows:
Rate = Z_{AB }e^{Ea/RT}
where Z_{AB }is the collision frequency. The number of collisions per second per unit volume of the reaction mixture is known as "collision frequency(Z)".
This chapter is a part of physical chemistry. There are some simple formulas and equations like zero order reaction, firstorder reaction, etc. which you must understand completely because these concepts are the root of this chapter.
Before reading this chapter, first, you must have the basic knowledge of the mole concept.
You must deeply observe how the graphs show some trends, how to find the rate constants from the graphs, how to find the order of the reactions, etc.
Rest this chapter is very simple, just be regular and be consistent in your numerical practice.
First, you must finish the class XII NCERT textbook and solve each and every example and unsolved question given in it. Then for advanced level preparation like JEE and NEET, you must follow R.C. Mukherjee and O.P. Tandon. You must definitely solve the previous year papers. Meanwhile, in the preparation, you must continuously write the mock tests for the depth of knowledge. This article will help you to provide with the variety of questions for deeper knowledge with the help of videos, articles and mock tests.
Chapters No. 
Chapters Name 
Chapter 1 

Chapter 2 

Chapter 3 

Chapter 4 

Chapter 5 

Chapter 6 

Chapter 7 

Chapter 9 

Chapter 10 

Chapter 11 

Chapter 12 

Chapter 13 

Chapter 14 

Chapter 15 

Chapter 16 

Chapter 17 

Chapter 18 

Chapter 19 

Chapter 20 

Chapter 21 

Chapter 22 

Chapter 23 

Chapter 24 

Chapter 25 

Chapter 26 

Chapter 27 

Chapter 28 
The halflife of a radioisotope is four hours. If the initial mass of the isotope was 200 g, the mass remaining after 24 hours undecayed is
1.042 g
2.084 g
3.125 g
4.167 g.
The halflife of a radioactive isotope is three hours. If the initial mass of the iosotope were 256 g, the mass of it remaining undecayed after 18 hours would be
4.0 g
8.0 g
12.0 g
16.0 g.
If halflife of a substance is 5 yrs, then the total amount of substance left after 15 years, when initial amount is 64 grams is
16 grams
2 grams
32 grams
8 grams