Law of Mass Action and Equilibrium Constant
Learn how to write equilibrium constant expressions (Kc, Kp) for chemical reactions, including the treatment of pure solids and liquids and the use of correct stoichiometric coefficients.
Why this shows up in the exam
NEET/JEE often test your ability to set up and manipulate equilibrium expressions for various types of reactions.
How NEET tests this
Practise it
These are real questions from past NEET papers that test this exact idea.
What is the [OH⁻] in the final solution prepared mixing 20.0 mL of 0.050 M HCl with 30.0 mL 0.10 M Ba(OH)₂?
Push further
More challenging9 harder questions built from the past papers above — a step up in difficulty, with distractors designed so you can't get there by elimination. Written and checked by our reviewers, not from a real paper.
Given the following equilibrium reactions and their constants: 1. 2SO₂(g) + O₂(g) ⇌ 2SO₃(g); K₁ 2. 2NO(g) + O₂(g) ⇌ 2NO₂(g); K₂ What is the equilibrium constant for the reaction SO₃(g) + NO(g) ⇌ SO₂(g) + NO₂(g)?
More from Equilibrium
Solubility Product and Solubility Equilibria (Ksp)
Calculate and interpret the solubility product (Ksp), relate it to molar solubility for various salts, and use it to predict precipitation and compare solubilities.
Buffer Solutions and Henderson-Hasselbalch Equation
Learn the composition, preparation, and mechanism of buffer solutions, and use the Henderson-Hasselbalch equation to calculate buffer pH and select appropriate buffers.
Acid-Base Theories
Understand the definitions and differences between Arrhenius, Brønsted-Lowry, and Lewis acid-base theories, including conjugate acid-base pairs and amphiprotic species.
Le Chatelier's Principle
Apply Le Chatelier's Principle to predict the effect of changes in concentration, pressure, and temperature on the position of equilibrium in chemical and phase equilibria.
Weak Acid and Base Equilibria
Analyze the equilibrium of weak acids and bases, calculate their dissociation constants (Ka, Kb), degree of dissociation, and related pH values.
pH and pOH Calculations
Calculate pH and pOH for strong and weak acids and bases, including very dilute solutions and mixtures.