Equilibrium

EquilibriumNEET Chemistry · Class 11 · NCERT Chapter 6

Overview Notes NEET Questions Interactive Learning

3 interactive concept widgets for Equilibrium. Drag any slider, change any number, and watch the formula and the answer update live. Built so you understand how each NEET problem actually works, not just the final number.

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Le Chatelier's principle simulator (9 stress types)

ICE table solver (3 preset reactions, step-by-step)

pH step-by-step calculator (strong/weak acid/base)

Le Chatelier's principle

Apply nine types of stress (concentration, pressure, temperature, inert gas) to three real reactions and see which way the equilibrium shifts and why.

Chemical equilibrium

Le Chatelier's principle simulator

Select a reaction and apply a stress (temperature, pressure, concentration, catalyst) to see which direction equilibrium shifts and why.

Le Chatelier's Principle: when a system at equilibrium is disturbed, it adjusts to oppose the disturbance.

N₂ + 3H₂ ⇌ 2NH₃

H₂ + I₂ ⇌ 2HI

N₂O₄ ⇌ 2NO₂

N₂(g) + 3H₂(g) ⇌ 2NH₃(g)

ΔH = -92 kJ/mol (exothermic) | Δn(gas) = -2

Apply a stress

Increase T

Decrease T

Increase P

Decrease P

Add reactant

Remove reactant

Add product

Remove product

Add catalyst

Select a stress above to see the equilibrium shift.

Try this

For H₂ + I₂ ⇌ 2HI: Δn = 0, so pressure changes have no effect. This is a classic NEET trap.
Catalyst: always "no shift" -- it speeds up both forward and backward reactions equally.
Haber process (NH₃): low T favors product (exothermic), high P favors product (fewer gas moles). Compromise: moderate T for acceptable rate.

ICE table and equilibrium concentrations

Walk through ICE (Initial-Change-Equilibrium) tables for three preset reactions. See each row fill in, the equilibrium expression set up, and the final concentrations calculated.

Chemical equilibrium

ICE table builder

Step through the Initial-Change-Equilibrium table for 3 preset problems. Click each row to reveal it and solve for equilibrium concentrations.

ICE tables help find equilibrium concentrations from initial concentrations and the equilibrium constant Kc.

Problem 1

Problem 2

Problem 3

A(aq) + B(aq) ⇌ C(aq)

Kc = 4 | [A]₀ = 1 M, [B]₀ = 1 M, [C]₀ = 0 M

Species

Initial (M)

Change

Equilibrium (M)

Try this

The "Change" row always has opposing signs: what is consumed on one side is produced on the other.
If Kc is very small (like 0.0117), x << initial concentrations. You can approximate by ignoring x in the denominator.
Check your answer: substitute back into the Kc expression to verify it equals the given Kc.

pH calculator

Calculate pH for strong acids, strong bases, weak acids, and weak buffers. Step-by-step working shown with the Henderson-Hasselbalch equation where relevant.

Ionic equilibrium

pH calculator

Calculate pH step by step for strong acids, strong bases, weak acids, and weak bases. Select from presets including HCl, NaOH, acetic acid, and ammonia.

Select a solution to calculate its pH with full step-by-step working.

HCl (0.1 M)

H₂SO₄ (0.05 M)

NaOH (0.1 M)

Ca(OH)₂ (0.01 M)

CH₃COOH (0.1 M)

HCOOH (0.1 M)

NH₃ (0.1 M)

C₅H₅N (0.1 M)

1.00

Nature

Acidic

Type

strong acid

Strong acid: fully ionizes in water.

[H⁺] = C = 1.00e-1 M

pH = −log₁₀[H⁺] = −log₁₀(1.00e-1) = 1.00

pH scale (0–14)

0 (very acidic)

7 (neutral)

14 (very basic)

Try this

For weak acids: pH = ½(pKa − log C). For CH₃COOH (pKa = 4.74, C=0.1 M): pH = ½(4.74 + 1) = 2.87.
Key formula: pH + pOH = 14 at 25°C. For NaOH (0.1 M): pOH = 1, pH = 13.
Degree of ionization α = √(Ka/C). Higher dilution → more ionization (higher α).

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Thermodynamics

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Redox Reactions

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