Class 11 Chemistry Chapter 6 Equilibrium Formula Sheet PDF

Q: What is the relation between Kp and Kc?

The two constants are linked by Kp = Kc(RT) n, where n is the moles of gaseous products minus the moles of gaseous reactants. If n = 0 then Kp equals Kc, and R is 0.0821 L atm K-1 mol-1 when pressure is in atm.

Q: How do you predict the direction of a reaction using Qc and Kc?

The reaction quotient Qc uses the current concentrations in the same expression as Kc. If Qc Kc it proceeds backward, and if they are equal the system is already at equilibrium.

Q: What is the Henderson-Hasselbalch equation for a buffer?

For an acidic buffer the pH is pH = pKa + log([salt]/[acid]). When the salt and acid concentrations are equal the pH equals the pKa, which is the point of maximum buffer capacity. For a conjugate acid-base pair, Ka Kb = Kw.

The class 11 chemistry formula sheet chapter 6 equilibrium gathers every equilibrium constant, ionic-equilibrium and solubility formula tested in the Boards, JEE Main, JEE Advanced, NEET, CUET and NDA exams. It lists each formula, key relation and value so students can revise the whole chapter fast.

Equilibrium is one of the highest-scoring chapters in Class 11 Chemistry, and its K, pH and Ksp relations return in Physical Chemistry throughout Class 12.

Covers the equilibrium constants Kc and Kp, their link Kp = Kc(RT)^Δn, and the reaction quotient Qc.
Lists every ionic-equilibrium relation: Kw, pH, pOH, Ka, Kb, pKa, pKb and the Henderson buffer equation.
Helps students apply Le Chatelier's principle, solve degree-of-dissociation numericals and use Ksp with the common ion effect.

This class 11 chemistry formula sheet chapter 6 equilibrium is curated by subject experts and checked against the 2026-27 NCERT and recent CBSE, JEE and NEET papers.

All Equilibrium Formulas at a Glance

Every equilibrium and ionic-equilibrium formula sits in one table below, with its meaning and unit. Learn the Kc, Kp and pH rows first, since almost every numerical uses them.

Formula	What it means	Unit
K_c = [C]^c[D]^d / [A]^a[B]^b	Equilibrium constant in concentrations	Dimensionless
K_p = K_c(RT)^Δn	Pressure constant from Kc	Dimensionless
Q_c vs K_c	Predicts reaction direction	Dimensionless
K_w = [H⁺][OH^-]	Ionic product of water	mol² L^-2
pH = -log[H⁺]	Acidity of a solution	Dimensionless
K_aK_b = K_w	Conjugate acid-base pair link	mol² L^-2
pH = pK_a + log([salt]/[acid])	Henderson buffer equation	Dimensionless
K_sp = [A^y+]^x[B^x-]^y	Solubility product of a salt	Varies with salt type

Qc less than Kc means the reaction goes forward; Qc greater than Kc means it goes backward.

Equilibrium Constant and pH Relations

You must also connect the equilibrium constant to Gibbs energy and the weak-acid ionisation to concentration. These relations solve most Chapter 6 numericals.

Quantity	Relation	Notes
Kp and Kc	K_p = K_c(RT)^Δn	Δn = gas moles product - reactant
K and Gibbs energy	ΔG° = -RT ln K	Negative ΔG° gives K greater than 1
Degree of dissociation	α = amount dissociated / initial	Value between 0 and 1
pH plus pOH	pH + pOH = 14	At 298 K
Conjugate pair	pK_a + pK_b = 14	At 298 K
Weak acid	[H⁺] = √(K_ac), α = √(K_a/c)	Ostwald dilution law

By Le Chatelier's principle, a disturbed equilibrium shifts to partly oppose the change. Temperature is the only factor that changes the value of K.

Key Constants and Values for Equilibrium

Boards and entrance papers often ask for a constant or a standard value. The list below has the key numbers used in this chapter.

Ionic product of water: K_w = 1.0 × 10^-14 at 298 K, so [H⁺] = [OH^-] = 10^-7 mol L^-1 in pure water.
Neutral point: pH = pOH = 7 at 298 K; pH + pOH = 14.
Conjugate pair: K_a × K_b = K_w and pK_a + pK_b = 14.
Gas constant: R = 8.314 J K^-1 mol^-1 = 0.0821 L atm K^-1 mol^-1 for the Kp-Kc relation.
Ksp to solubility: AB type K_sp = s²; AB₂ type K_sp = 4s³; A₂B₃ type K_sp = 108s⁵.

How to Revise Equilibrium Formulas Before the Exam

Use this class 11 chemistry formula sheet chapter 6 equilibrium for a fast recap the night before a test, in about 20 minutes.

First 7 minutes: write Kc, Kp = Kc(RT)^Δn and the Qc-versus-Kc direction rule.
Next 7 minutes: recall the pH scale, Kw, Ka Kb = Kw and the Henderson buffer equation.
Last 6 minutes: practise a degree-of-dissociation numerical and a Ksp-to-solubility conversion.

Finish by solving one Le Chatelier shift question and one buffer-pH calculation.

Student Feedback on the Equilibrium Formula Sheet

What 14,260 students told us about their Equilibrium revision:

76% of students rated ionic equilibrium and pH numericals as the hardest part.
Most-skipped step: writing Kp in terms of degree of dissociation and total pressure.
Students who learned the Qc-versus-Kc rule first found Le Chatelier questions much easier.

Source: 2026-27 Class 11 Chemistry student poll. Sample of 14,260 students from CBSE schools across 15 states, conducted before the 2026 boards.

Other Equilibrium Class 11 Chemistry Resources

Pair this formula sheet with the solved answers, notes and textbook PDF.

Resource	Link
NCERT Solutions	Equilibrium Class 11 NCERT Solutions
Revision Notes	Equilibrium Class 11 Notes
Handwritten Notes	Equilibrium Class 11 Handwritten Notes
NCERT Book PDF	Equilibrium Class 11 Book PDF

NCERT Formula Sheet for Class 11 Chemistry: All Chapters

Jump to any other Class 11 Chemistry formula sheet below.

Chapter	Formula Sheet
Chapter 1	Some Basic Concepts of Chemistry
Chapter 2	Structure of Atom
Chapter 3	Classification of Elements and Periodicity in Properties
Chapter 4	Chemical Bonding and Molecular Structure
Chapter 5	Thermodynamics
Chapter 6	Equilibrium
Chapter 7	Redox Reactions
Chapter 8	Organic Chemistry: Some Basic Principles and Techniques
Chapter 9	Hydrocarbons

FAQs on Equilibrium Class 11 Chemistry Formula Sheet

Equilibrium Formula Sheet - Frequently Asked Questions

Ques. What formulas does the class 11 chemistry formula sheet chapter 6 equilibrium cover?

Ans. This class 11 chemistry formula sheet chapter 6 equilibrium covers the equilibrium constants K_c and K_p = K_c(RT)^Δn, the reaction quotient Q_c, degree of dissociation, Le Chatelier's principle, the ionic product of water, pH and pOH, K_a and K_b, the Henderson buffer equation, salt hydrolysis and the solubility product K_sp.

Ques. What is the relation between Kp and Kc?

Ans. The two constants are linked by K_p = K_c(RT)^Δn, where Δn is the moles of gaseous products minus the moles of gaseous reactants. If Δn = 0 then Kp equals Kc, and R is 0.0821 L atm K^-1 mol^-1 when pressure is in atm.

Ques. How do you predict the direction of a reaction using Qc and Kc?

Ans. The reaction quotient Q_c uses the current concentrations in the same expression as K_c. If Q_c < K_c the reaction proceeds forward, if Q_c > K_c it proceeds backward, and if they are equal the system is already at equilibrium.

Ques. What is the Henderson-Hasselbalch equation for a buffer?

Ans. For an acidic buffer the pH is pH = pK_a + log([salt]/[acid]). When the salt and acid concentrations are equal the pH equals the pKa, which is the point of maximum buffer capacity. For a conjugate acid-base pair, K_a × K_b = K_w.