JEE 2022 | Class 12
banner-image

Chemical Equilibrium

Get plus subscription and access unlimited live and recorded courses

Introduction

Chemical equilibrium is defined as the state in which both products and reactants are present in the present concentrations which have no further tendency to change with time so that there is no observable change in the properties of the system which is present. This results in the state when the forward reaction proceeds at the same rate as the reverse reaction. The reaction rates of the backward and forward reactions are generally not zero, but equal. Thus, no net changes are seen in the concentrations of reactants and products. Such a state is called a dynamic equilibrium state.


Historical Introduction

Berthollet developed a chemical equilibrium in 180, he found that some chemical reactions are reversible. Forward and backward (reverse) reaction rates are equal for any reaction mixture to exist at equilibrium. Arrows pointing both ways to indicate equilibrium in the following chemical equation, where A and B are reactant chemical species, product species are S and T, and the stoichiometric coefficients α, β, σ, and τ are of the respective reactants and products.


"Far to the right" is said to lie to the equilibrium concentration position of a reaction if, at equilibrium, nearly all the reactants are consumed.  "Far to the left" is said Conversely to the equilibrium position if hardly any product is formed from the reactants.

 

Based on Berthollet's ideas, Guldberg and Waage in 1865, proposed the law of mass action, where A, B, S, and T are active masses and k+ and k are rate constants.

 

The numerator is formed from the products by convention. For the reaction of one-step, the mass law action is only valid, that proceed through a single transition state and is not valid in general because the rate of equations do not, in general, follow the reaction of stoichiometry as Guldberg and Waage had proposed (see, for example, nucleophilic aliphatic substitution by SN1 or reaction of hydrogen and bromine to form hydrogen bromide). However, for chemical equilibrium, the equality of forwarding and backward reaction rate is a necessary condition, though it is not sufficient to explain why equilibrium occurs.

 

The constant of equilibrium for a reaction is indeed a constant even despite the failure of this derivation, activities independent of any of the various species involved, though it is temperature-dependent as observed by the van 't Hoff equation. A catalyst addition will affect both the forward reaction and the reverse reaction in the same way and will not have an effect on the equilibrium constant. Both reactions will speed up by the catalyst and increase the speed at which the equilibrium is reached.


Types

Reactions do occur at the molecular level, Although the macroscopic equilibrium concentrations are constant in time. For example, when the acetic acid dissolved in water it  forms acetate and hydronium ions,

CH3CO2H + H2O ⇌ CH3CO−2 + H3O+


Types of Chemical Equilibrium

There are two types of chemical equilibrium:

  • Homogeneous Equilibrium

  • Heterogeneous Equilibrium


Homogeneous Chemical Equilibrium

In Homogeneous Equilibrium, the reactants and the products of chemical equilibrium are all in the same phase. It can be further divided into two types: 

a) Reactions in which the number of molecules of the products is equal to the number of molecules of the reactants. For example,

  • H2 (g) + I2 (g) ⇌ 2HI (g)

  • N2 (g) + O2 (g) ⇌ 2NO (g)

b) Reactions in which the number of molecules of the products is not equal to the total number of reactant molecules. For example,

  • 2SO2 (g) + O2 (g) ⇌ 2SO3 (g)

  • COCl2 (g) ⇌ CO (g) + Cl2 (g)


Heterogeneous Chemical Equilibrium

In, Heterogeneous Equilibrium the reactants and the products of chemical equilibrium are present in different phases. Examples of heterogeneous equilibrium are listed below.

  • CO2 (g) + C (s) ⇌ 2CO (g) 

  • CaCO3 (s) ⇌ CaO (s) + CO2 (g)

Thus, the different types of chemical equilibrium are based on the phase of the reactants and products.


Factors Affecting Chemical Equilibrium

Temperature, pressure, and concentration of the system which affect equilibrium are several factors. Some of the important factors affecting chemical equilibrium are discussed below.


Change in Pressure:

Due to the change in the volume, the change in pressure happens. The gaseous reaction can be affected If there is a change in pressure, as the total number of gaseous reactants and products are now different. As per Le Chatelier’s principle, in heterogeneous chemical equilibrium, as the volume is independent of pressure, the change of pressure in both liquids and solids can be ignored.


Change in Temperature:

The temperature effect on chemical equilibrium depends upon the sign of ΔH of the reaction and follows Le-Chatelier’s Principle.

  • The equilibrium constant of an exothermic reaction decreases as temperature increases.

  • The equilibrium constant increases in an endothermic reaction with an increase in temperature.

The rate of reaction is also affected along with equilibrium constant, by the change in temperature. According to Le Chatelier’s principle, the equilibrium shifts towards the reactant side when the temperature increases in case of exothermic reactions, for endothermic reactions the equilibrium shifts towards the product side with an increase in temperature.

See More
JEE Advanced Important Dates

JEE Advanced Important Dates

View All Dates
JEE Advanced 2022 exam date and revised schedule have been announced by the NTA. JEE Advanced 2022 will now be conducted on 28-August-2022, and the exam registration closes on 11-August-2022. You can check the complete schedule on our site. Furthermore, you can check JEE Advanced 2022 dates for application, admit card, exam, answer key, result, counselling, etc along with other relevant information.
See More
View All Dates
JEE Advanced Information

JEE Advanced Information

Application Form
Eligibility Criteria
Reservation Policy
Admit Card
IIT Bombay has announced the JEE Advanced 2022 application form release date on the official website https://jeeadv.ac.in/. JEE Advanced 2022 Application Form is available on the official website for online registration. Besides JEE Advanced 2022 application form release date, learn about the application process, steps to fill the form, how to submit, exam date sheet etc online. Check our website for more details.
JEE Advanced 2022 applicants should be aware of the eligibility criteria before applying to the exam. IIT Bombay has released all the relevant information on the official website, i.e. https://jeeadv.ac.in/. JEE Advanced 2022 aspirants should have passed Class 12th or any other equivalent qualifying examination in 2021, 2020, or students appearing in the Class 12th final exam in 2022 can also apply. For further details, visit our website.
As per the union government’s norms, IIT Bombay has released the JEE Advanced 2022 reservation criteria for different candidates’ categories (SC/ST/OBC/PwD), All India Quota, State Government Quota, Deemed Universities, and more. You can check more details on Vedantu website.
JEE Advnced 2022 Admit Card will be released by the IIT Bombay in the month of August 2022. Candidates can download the JEE Advanced admit card and hall ticket from the JEE Advanced official website i.e. https://jeeadv.ac.in/. For more details on the JEE Advanced admit card 2022, candidates can check Vedantu official website.
It is crucial for the the engineering aspirants to know and download the JEE Advanced 2022 syllabus PDF for Maths, Physics and Chemistry. Check JEE Advanced 2022 syllabus here along with the best books and strategies to prepare for the entrance exam. Download the JEE Advanced 2022 syllabus consolidated as per the latest NTA guidelines from Vedantu for free.
See More
Download full syllabus
Download full syllabus
View JEE Advanced Syllabus in Detail
JEE Advanced 2022 Study Material

JEE Advanced 2022 Study Material

View all study material for JEE Advanced
JEE Advanced 2022 Study Materials: Strengthen your fundamentals with exhaustive JEE Advanced Study Materials. It covers the entire JEE Advanced syllabus, DPP, PYP with ample objective and subjective solved problems. Free download of JEE Advanced study material for Physics, Chemistry and Maths are available on our website so that students can gear up their preparation for JEE Advanced exam 2022 with Vedantu right on time.
See More
All
Chemistry
Maths
Physics
See All
JEE Advanced Question Papers

JEE Advanced Question Papers

see all
Download JEE Advanced Question Papers & ​Answer Keys of 2022, 2021, 2020, 2019, 2018 and 2017 PDFs. JEE Advanced Question Paper are provided language-wise along with their answer keys. We also offer JEE Advanced Sample Question Papers with Answer Keys for Physics, Chemistry and Maths solved by our expert teachers on Vedantu. Downloading the JEE Advanced Sample Question Papers with solutions will help the engineering aspirants to score high marks in the JEE Advanced examinations.
See More
JEE Advanced 2022 Book Solutions and PDF Download

JEE Advanced 2022 Book Solutions and PDF Download

View all JEE Advanced Important Books
In order to prepare for JEE Advanced 2022, candidates should know the list of important books i.e. RD Sharma Solutions, NCERT Solutions, HC Verma books and RS Aggarwal Solutions. They will find the high quality readymade solutions of these books on Vedantu. These books will help them in order to prepare well for the JEE Advanced 2022 exam so that they can grab the top rank in the all India entrance exam.
See More
Maths
NCERT Book for Class 12 Maths
Physics
NCERT Book for Class 12 Physics
Chemistry
NCERT Book for Class 12 Chemistry
Physics
H. C. Verma Solutions
Maths
R. D. Sharma Solutions
Maths
R.S. Aggarwal Solutions
See All
JEE Advanced Mock Tests

JEE Advanced Mock Tests

View all mock tests
JEE Advanced 2022 free online mock test series for exam preparation are available on the Vedantu website for free download. Practising these mock test papers of Physics, Chemistry and Maths prepared by expert teachers at Vedantu will help you to boost your confidence to face the JEE Advanced 2022 examination without any worries. The JEE Advanced test series for Physics, Chemistry and Maths that is based on the latest syllabus of JEE Advanced and also the Previous Year Question Papers.
See More
JEE Advanced 2022 Cut-Off

JEE Advanced 2022 Cut-Off

JEE Advanced Cut Off
IIT Bombay is responsible for the release of the JEE Advanced 2022 cut off score. The qualifying percentile score might remain the same for different categories. According to the latest trends, the expected cut off mark for JEE Advanced 2022 is 50% for general category candidates, 45% for physically challenged candidates, and 40% for candidates from reserved categories. For the general category, JEE Advanced qualifying marks for 2021 ranged from 17.50%, while for OBC/SC/ST categories, they ranged from 15.75% for OBC, 8.75% for SC and 8.75% for ST category.
See More
JEE Advanced 2022 Results

JEE Advanced 2022 Results

JEE Advanced 2022 Result - IIT Bombay has announced JEE Advanced result on their website. To download the Scorecard for JEE Advanced 2022, visit the official website of JEE Advanced i.e https://jeeadv.ac.in/.
See More
Rank List
Counselling
Cutoff
JEE Advanced 2022 State Wise Rank List - The respective state authorities started releasing the JEE Advanced 2022 state merit lists for admission to Engineering course. Check JEE Advanced 2022 state-wise rank list for the year 2022 here.
The IIT Bombay will conduct JEE Advanced 2022 counselling at https://jeeadv.ac.in/. There will be six rounds of counselling for admission under All India Quota (AIQ), IITs. A mop-up round of JEE Advanced counselling will be conducted excluding 15% AIQ seats, while the dates of JEE Advanced 2022 counselling for 85% state quota seats will be announced by the respective state authorities.
IIT Bombay is responsible for the release of the JEE Advanced 2022 cut off score. The qualifying percentile score might remain the same for different categories. According to the latest trends, the expected cut off mark for JEE Advanced 2022 is 50% for general category candidates, 45% for physically challenged candidates, and 40% for candidates from reserved categories. For the general category, JEE Advanced qualifying marks for 2021 ranged from 17.50%, while for OBC/SC/ST categories, they ranged from 15.75% for OBC, 8.75% for SC and 8.75% for ST category.
Want to know which Engineering colleges in India accept the JEE Advanced 2022 scores for admission to Engineering? Find the list of Engineering colleges accepting JEE Advanced scores in India, compiled by Vedantu. There are 1622 Colleges that are accepting JEE Advanced. Also find more details on Fees, Ranking, Admission, and Placement.
See More
question-image

FAQs on Chemical Equilibrium

FAQ

Q1. Give Some Everyday Examples of Chemical Equilibrium.

Ans: The everyday examples of chemical equilibrium is when we are steady and calm. An example of it is when cold air and hot air are entering the room at the same time so that the overall temperature of the room does not change at all.

Q2. What All Things Can Dispute the Chemical Equilibrium?

Ans: There are three types of stresses that can alter the composition of an equilibrium system, removing or adding reactants or the products, changing total pressure or volume and the temperature of the system.

Q3. Give Applications of Equilibrium Constraints.

Ans: The equilibrium constraints allow us to predict the products and reactants for chemical processes. The equilibrium constant depends on the pre-equilibrium constraints of the products and reactants.

Q4. Mention the Factors Which Affect Chemical Equilibrium.

Ans: The concentration change, temperature, and pressure can affect the position of a reversible reaction equilibrium reaction. Equilibrium occurs when a certain proportion of a mixture exists as a reactant and the rest exits as a product.