Chemistry · Class 12 · Chemical Kinetics

Chemical Kinetics for JEE

Everything you need for this topic on one page: the ideas, the formulas, the traps, and free lectures that explain it well.

Last updated: 26 October 2026

Direct answer

Rate of reaction, rate law, order and molecularity, integrated rate equations, half-life and the Arrhenius equation.

Key ideas

Chemical Kinetics: what you must understand

Order is found from experiment; molecularity from the elementary step
First-order half-life does not depend on concentration
Catalysts lower activation energy, not ΔH
A 10 °C rise often roughly doubles the rate

Formula sheet

Must-know formulas for Chemical Kinetics

First order: k = (2.303/t) log([A]₀/[A])
t½ (first order) = 0.693/k; zero order: [A]₀/2k
Arrhenius: k = A e^(−Eₐ/RT)
log(k₂/k₁) = Eₐ/(2.303R)(1/T₁ − 1/T₂)

One-page formula sheet

Printable Chemical Kinetics formula sheet: formulas, key ideas and traps on one page. Save it as a PDF for offline revision.

Avoid

Common mistakes students make

Confusing order with molecularity
Using first-order half-life for other orders
Wrong units of k

For the exam

How this topic is asked in JEE

Appears frequently. Frequent and formula-based. Units of k tell you the order instantly.

NCERT map

Where Chemical Kinetics is in NCERT

Chapter names follow the current rationalised NCERT textbooks. Read these sections before solving PYQs.

Class	Book	Chapter	Sections JEE asks from
Class 12	Chemistry Part I	Chemical Kinetics	Rate of a Chemical Reaction; Factors Influencing Rate of a Reaction; Integrated Rate Equations; Half-Life of a Reaction; Temperature Dependence of the Rate of a Reaction

JEE Advanced level

A JEE Advanced-level example on Chemical Kinetics

Question. A first-order reaction A → B has a rate constant k₁ = 2.0 × 10⁻³ s⁻¹ at 300 K. The activation energy for this reaction is 50 kJ/mol. At what temperature will the half-life of this reaction be 100 seconds? Also, if the initial concentration of A is 0.5 M, find the concentration of A after 200 seconds at this new temperature. (R = 8.314 J/mol·K)

Show solution

For first-order reactions, t₁/₂ = 0.693/k. If t₁/₂ = 100 s, then k₂ = 0.693/100 = 6.93 × 10⁻³ s⁻¹
Apply Arrhenius equation: ln(k₂/k₁) = (Eₐ/R) × (1/T₁ − 1/T₂). Substituting: ln(6.93 × 10⁻³ / 2.0 × 10⁻³) = (50000/8.314) × (1/300 − 1/T₂)
Solving: ln(3.465) = 6014.4 × (1/300 − 1/T₂), which gives 1.243 = 6014.4 × (3.333 × 10⁻³ − 1/T₂)
Rearranging: 1/T₂ = 3.333 × 10⁻³ − 2.067 × 10⁻⁴ = 3.126 × 10⁻³, so T₂ = 320 K
For concentration, use first-order integrated rate law: ln([A]₀/[A]) = k₂t = 6.93 × 10⁻³ × 200 = 1.386
Therefore [A] = 0.5/e^1.386 = 0.5/4 = 0.125 M (which equals concentration after 2 half-lives)

Answer: Temperature T₂ = 320 K and concentration [A] = 0.125 M

This example was solved twice independently and both solutions agree.

Free lectures

Best free lectures for Chemical Kinetics

Full-chapter free lectures picked from YouTube search results by views, from established JEE channels (mostly in Hinglish). Use the subtopic list to jump straight to the part you need (timestamps come from each video's own chapter list). Watch one, then solve PYQs the same day.

CHEMICAL KINETICS in One Shot: All Concepts & PYQs Covered | JEE Main & Advanced — JEE Wallah, 5:04:54
Jump to a subtopic (12)
- 00:00 Introduction
- 05:37 Chemical kinetics
- 08:58 Rate of reaction
- 22:50 Average and instantaneous rate
- 42:15 Rate law or rate equation
- 49:14 Order of reaction
- 1:29:56 Molecularity
- 1:48:44 Integrated rate equation
- 3:29:21 Factors affecting rate of reaction
- 4:05:47 Collision theory
- 4:41:12 First order parallel reactions
- 5:00:33 Thank You Bachhon!
CHEMICAL KINETICS in 1 Shot - All Concepts Covered || JEE Main & Advanced || Class 12 — Lakshya JEE, 2:49:01
Jump to a subtopic (15)
- 00:00 Introduction
- 02:50 Applications of mole concept
- 06:18 Rate of reaction
- 42:08 Factors affecting Rate of reaction
- 48:45 Rate law
- 1:02:22 Molecularity and Order
- 1:15:10 Rate constant
- 1:19:52 Zero Order kinetics
- 1:34:14 First Order kinetics
- 1:54:30 Second Order kinetics
- 1:58:59 Parallel reaction
- 2:16:19 Collision theory
- 2:34:09 Catalyst
- 2:42:37 Sequential reaction
- 2:48:58 Thankyou bachhon!

Practise

Where to practise for free

13 JEE Main 2026 PYQs on Chemical Kinetics, with solutions.
Read the chapter in NCERT textbooks (official, free), then solve its NCERT Exemplar (official, free) questions.
Chapter-wise past questions: JEE Main and Advanced PYQs and question bank.
Timed practice tests: NTA Abhyas practice tests (official, free) and our free mock tests.
See it move: interactive simulation.

FAQs

Frequently asked questions

Is Chemical Kinetics important for JEE Main 2027?

Appears frequently. It is part of the official 'Chemical Kinetics' unit in the JEE Main 2027 syllabus.

What are the most important formulas in Chemical Kinetics?

First order: k = (2.303/t) log([A]₀/[A]); t½ (first order) = 0.693/k; zero order: [A]₀/2k; Arrhenius: k = A e^(−Eₐ/RT).

How should I study Chemical Kinetics for JEE?

Understand the key ideas from NCERT or one full lecture, learn the formula sheet, then solve 25–30 past JEE questions on the topic. Frequent and formula-based. Units of k tell you the order instantly.