Methods of Separation - Crystallisation Method

Topics

Some Basic Concepts of Chemistry
Introduction to Analytical Chemistry
- Introduction of Analytical Chemistry
- Analysis
- Mathematical Operation and Error Analysis
- Determination of Molecular Formula
- Chemical Reactions and Stoichiometric Calculations
- Limiting Reagent
- Concentration of a Solution
- Use of Graph in Analysis
Basic Analytical Techniques
- Introduction of Some Analytical Techniques
- Purification of Solids
- Crystallisation Method
- Fractional Crystallization
- Simple Distillation Method
- Solvent Extraction
- Chromatography Method
- Chromatography Method > Adsorption Chromatography
- Chromatography Method > Partition Chromatography
Structure of Atom
Chemical Bonding
Redox Reactions
Modern Periodic Table
- Introduction of Periodic Table
- Structure of the Modern Periodic Table
- Periodic Table and Electronic Configuration
- Blockwise Characteristics of Elements
- Periodic Trends in Elemental Properties
Elements of Group 1 and 2
Elements of Group 13, 14 and 15
- Electronic Configuration of Elements of Groups 13, 14 and 15
- Trends in Atomic and Physical Properties of Elements of Groups 13, 14 and 15
- Chemical Properties of the Elements of the Groups 13,14 and 15
- Carbon: A Versatile Element
- Allotropes of Carbon > Diamond
- Molecular Structures of Some Important Compounds of the Group 13, 14 and 15 Elements
- Chemistry of Notable Compounds of Elements of Groups 13, 14 and 15
States of Matter
Adsorption and Colloids
Chemical Equilibrium
- Introduction of Chemical Equilibrium
- Equilibrium in Physical Processes
- Equilibrium in Chemical Processes - Dynamic Equilibrium
- Law of Mass Action and Equilibrium Constant
- Homogeneous Equilibria
- Characteristics of Equilibrium Constant
- Applications of Equilibrium Constants
- Le Chaterlier's Principle and Factors Altering the Composition of Equilibrium
- Industrial Application
Nuclear Chemistry and Radioactivity
- Introduction: Nuclear Chemistry is a Branch of Physical Chemistry
- Classification of Nuclides
- Nuclear Stability
- Radioactivity
- Radioactive Decays
- Modes of Decay
- Nuclear Reactions
- Applications of Radio Isotopes
Basic Principles of Organic Chemistry
- Organic Chemistry
- Structural Representation of Organic Molecules
- Classification of Organic Compounds
- Nomenclature
- Isomerism
- Theoretical Basis of Organic Reactions
Hydrocarbons
Chemistry in Everyday Life

Estimated time: 2 minutes

CBSE: Class 12

Key Points: Crystallisation Method

Based on difference in solubility of the compound and impurities at different temperatures.
Compound more soluble in hot solvent → dissolved at high temperature → cooled → pure crystals form → impurities remain in solution (mother liquor).
Common solvents: water, alcohol, ether, chloroform, acetone, benzene, petroleum ether.
Example: Benzoic acid (slightly soluble in cold water, completely soluble in hot water) → separated from naphthalene.
Fractional crystallisation: Used when two compounds have different solubilities in the same solvent → less soluble crystallises first on cooling (e.g., K₂CO₃ and KCl).