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JEE Advanced Chemical Kinetics Important Questions

Last updated date: 27th Nov 2023
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MVSAT Dec 2023

JEE Advanced Important Questions of Chemical Kinetics

Chemistry is one of the scoring subjects when compared to the other subjects in JEE Advanced. IIT JEE Advanced Chemical Kinetics important questions are provided in detail for Chemistry. Each and every question asked comes with a detailed step by step solution along with a diagrammatic explanation to help students understand the concepts thoroughly. Our subject matter experts who have years of experience have prepared these solutions to the important questions. These will help students in the last minute preparations as well.


JEE Advanced Important Questions


Text, Images, Videos and PDF


JEE Advanced

Chapter Name:

Chemical Kinetics

Academic Session:



English Medium



Available Material:

Chapter-wise Important Questions with PDF

Topics of Chemical Kinetics

  1. Rates of Chemical Reactions:

Rates of chemical reactions, explored through order and molecularity, dictate how fast reactions occur. The rate law, a crucial formula, delves into the factors influencing reaction speed. Imagine it as the tempo of a chemical dance—understanding these concepts is key to predicting and controlling reaction rates. 

  1. Rate Constant:

This constant, denoted as 'k,' is a key player in the rate law formula. Picture it as the conductor guiding the tempo of a symphony—understanding the rate constant allows you to predict and control the pace of chemical reactions.

  1. Half-Life; Differential and Integrated Rate Expressions for Zero and First Order Reactions:

The concept of half-life is like a time capsule, revealing the duration for a reaction to reach halfway completion. Differential and integrated rate expressions for zero and first order reactions provide the mathematical backbone to understand reaction rates. Temperature dependence of the rate constant, unveiled through the Arrhenius equation and activation energy, is like adjusting the heat to control the pace of a culinary masterpiece. Catalysis, whether homogeneous or heterogeneous, acts as a guide, expediting reactions without being consumed, akin to a skilled chef enhancing flavors. 

  1. Activity and Selectivity of Solid Catalysts:

Picture these catalysts as skilled matchmakers in a reaction dance, influencing selectivity and activity. They guide the reactants, enhancing the desired product's formation without undergoing any change themselves. Activity measures their efficiency, like a matchmaker's success rate, while selectivity reflects their precision in steering reactions toward specific outcomes.

  1. Enzyme Catalysis and its Mechanism:

Enzymes are like molecular maestros orchestrating chemical symphonies. They accelerate reactions with remarkable specificity, acting as matchmakers for molecules. The mechanism involves an enzyme embracing the reactants, creating a conducive environment for transformation, and then releasing the products unaltered. It's akin to a conductor guiding musicians through a harmonious performance.

Important Formulas of Chemical Kinetics

  1. Rate of Reaction and Average Rate:

$Hg(1) + Cl_{2}\rightarrow HgCl_{2}(s);$

Rate of Reaction

$= - \frac{\Delta [Hg]}{\Delta t} = \frac{\Delta [Cl_{2}]}{\Delta t} = + \frac{\Delta [HgCl_{2}]}{\Delta t}$

$2Hl(g) \rightarrow H_{2}(g) + l_{2}(g)$

Rate of Reaction

$= - \frac{1}{2}\frac{\Delta [Hl]}{\Delta t} = + \frac{\Delta [H_{2}]}{\Delta t} = + \frac{\Delta [l_{2}]}{\Delta t}$

  1. Unimolecular Reaction:

$NH_{4}NO_{2}\rightarrow N_{2} + 2H_{2}O$

  1. Biomolecular Reaction:

$2HI(g)\rightarrow H_{2}(g)+ I_{2}(g)$

  1. Trimolecular Reaction:

$2NO(g) + O_{2}(g)\rightarrow 2NO_{2}(g)$

  1. Zero Order Reaction:

$k = \frac{2.303}{t} log \frac{a}{a-x} or k = \frac{2.303}{t} log \frac{[A_{0}]}{[A]}$

  1. Velocity of Chemical Reaction:

$Rate = \frac{\Delta c}{\Delta d}= mollit^{-1}time^{-1} = moldm^{-3}time^{-1}$

Ace Your JEE Advanced Chemistry Chemical Kinetics Exam with Our Practice Papers

Our JEE Advanced Chemistry Chemical Kinetics practice paper are designed to help you score high in the exam. With targeted questions and in-depth solutions, these papers will boost your preparation and help you secure a top score. Download the PDFs from Chemistry Chemical Kinetics practice papers.

Competitive Exams after 12th Science

Chemical Kinetics Important Questions for JEE Advanced

In this chapter, you will learn about the chemical changes which will result in chemical kinetics, it is basically the study of the flow and rate of chemical processes and the other name to chemical kinetics is reaction kinetics.  Students who are preparing for the JEE Advanced examination, it is recommended to have a clear understanding of each and every topic of chemistry. The most interesting topic under Chemical Kinetics is Elementary reactions, the concentration of reactants or products, molecularity of reactions and Rate law: Law of mass action. Mainly, you can learn about how fast a reaction proceeds and also does a reaction take place

Before we proceed to the questions, let us quickly walk you through how Vedantu will help students in their preparation for the JEE Advanced and boost their chances of scoring well:

  • Dedicated articles covering every topic, under every subject of the JEE Syllabus.

  • PDFs that can be downloaded and viewed offline, anytime and anywhere.

  • Solutions provided in every document, so students don’t have to wait to check their answers.

  • Strictly abiding by the official pattern of the JEE exam.

  • Prepared by subject experts who are backed by immense experience in the academic field.

  • Answers provided to the most frequently asked questions.

The weightage of this unit is 8 marks in the final examination which is around 6% to 7%. Chemical Kinetics comes in paper 2 of JEE Advanced. Chemical Kinetics is a part of Physical chemistry and this topic is most important among all the other topics under Physical chemistry. Our subject matter experts have explained the solutions in an easy and understandable language.


Understand the dance of reaction tempos through order, molecularity, and the vital rate constant 'k.' Concepts like half-life and rate expressions act as time capsules, revealing reaction durations and mathematical foundations. Dive into temperature dependence with the Arrhenius equation, unravelling the culinary artistry of reaction control. Catalysts, whether solid or enzymatic, influence reaction selectivity, orchestrating chemical symphonies. Vedantu's practice papers elevate JEE Advanced preparation.

FAQs on JEE Advanced Chemical Kinetics Important Questions

1. What is meant by the ‘rate’ of a chemical reaction according to JEE Advanced Chemical Kinetics Important Questions?

The rate of a chemical reaction, also known as the ‘reaction rate’ is the speed at which the reactants are converted to products. There are various reactions that take place almost instantaneously and also many other reactions that take a long, long time. Depending on the time taken by the reaction to fully convert all of its reactants to products, they can be classified as fast reactions, moderate reactions or slow (esterification) reactions. Alternatively, the rate of a reaction can also be defined as the rate of appearing of the products or the rate of disappearing of the reactants.

2. How do you determine the unit of the rate constant ‘k’?

As we have learned, the rate of a reaction is the speed with which the products appear or reactants disappear. This rate is directly proportional to the concentration of the reaction. Let’s take an example to fully understand this:

Consider the following chemical reaction:

aA + bB → cC + dD

Thus, Rate is directly proportional to (A)x(B)y

In order to remove the proportionality, we will introduce a constant of proportionality called the ‘Rate constant’ and denote it by k.

Rate = kAxBy

Where x and y are stoichiometric coefficients. The sum of x and y determine the order of the reaction. 

Order = x + y

Depending on the order of the reaction, the units of k are as follows:


Unit of k


mol L-1 s-1




mol-1L s-1

3. In simple terms, how would you define the half life of a chemical reaction?

The time taken by the reaction to reduce the concentration of the reactants to half their initial value is known as the half life of the chemical reaction. It is denoted as t1/2. This value is used all round the medicine field in order to calculate the concentration of a given reactant at any given point of time. Depending on the order of the chemical reaction, the formula of half life of a reaction can be listed as:

Zero Order: t1/2 = 0.693/k

First Order: t1/2 =2.303tlog(2)0.693k

Where k is the rate constant. Students are expected to make note of these formulas since it is frequently asked in the exam. You can also check this article to know more about half life.

4. Mention some factors that affect the rate of the chemical reaction.

There are various factors that affect the rate of a chemical reaction, some influencing it whilst other making it slower. A few of them have been listed down below:

  1. Physical state of the reactants:  Gaseous reactants convert fastest to the product, followed by liquid and solid reactants. 

  2. Rate depending on state : Gaseous state> Liquid state>Solid state

  3. Size of the reactants: The rate of the reaction is inversely proportional to the size of the reactants; larger the size, slower is the speed of conversion from reactants to products.

  4. Concentration of the reactants: The rate of the reaction is directly proportional to the concentration, where more the concentration, faster the reaction takes place.

Read the textbook thoroughly to know more about other influencing factors such as temperature, chemical nature of the reactants, etc.

5. What are some important formulas mentioned in the JEE Advanced Chemical Kinetics Important Questions?

Chemical kinetics is loaded with tons of formulas that come in handy while solving the JEE paper. Not only is it helpful for this chapter, but also helps in the understanding of further chapters like Chemical equilibrium. Listing some important formulas down below:

Rate of reaction:

Rate of Reaction = \[\frac{Increase\: in\: Concentration\: of\: Product}{Time\: taken}\]=\[\frac{Decrease\: in\: Concentration\: of\: Reactant}{Time\: taken}\]

Unit of rate constant:


Unit of k


mol L-1 s-1




mol-1L s-1

Half life:

Zero Order: t1/2 = 0.693/k

First Order: t1/2 =2.303tlog(2)0.693k

Arrhenius Equation

\[K = Ae \frac{-Ea}{RT} \]

To know about each of the topics in detail, you can visit Chemical Kinetics - Definition, Formula, Equations and FAQs.

We hope you found this article useful and that you were able to solve the questions given in the document. What we seriously recommend the students to do is to carefully go through the solution given under each of the questions and try to check not only if your answer was correct but also if the method you used what's the most efficient one to get to the correct answer. How you manage your time is one of the key factors that determine whether you succeed in the JEE advanced and hence using the shortest path to get to the solution is just as important as getting to the right solution.

Students need to also make sure that if you could solve most of these questions on your own, you indeed are on the right path, but it is very important that you don't grow complacent. On the other hand if you struggled solving most of these questions, and constantly found yourself referring to the solution, it is nothing but a wakeup call that you need to relearn or revise this topic once again just to get a hold of it. In either case we are sure this article will help you prepare for the chemical kinetics topic which is very essential for the JEE advanced. Visit our official website for more such articles covering different subjects and topics that fall under the JEE syllabus.