Solutions 12 Chemistry — Revision Notes
Solutions are homogeneous mixtures of solute and solvent with uniform composition. Understanding solubility, concentration, and colligative properties is e
TL;DR: Solutions are homogeneous mixtures of solute and solvent with uniform composition. Understanding solubility, concentration, and colligative properties…
Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated
Solutions are homogeneous mixtures of solute and solvent with uniform composition. Understanding solubility, concentration, and colligative properties is e
Types of Solutions
- Solution is homogeneous mixture of solute and solvent
- Solute is substance dissolved; solvent is substance doing dissolving
- Aqueous solutions have water as solvent
- Non-aqueous solutions use other solvents like alcohol or benzene
- Solutions can be gaseous, liquid, or solid
Solubility and Factors Affecting It
- Solubility is amount of solute that dissolves in solvent at given temperature
- Temperature affects solubility; most solids increase with temperature
- Pressure affects gas solubility significantly; Henry's Law applies
- Like dissolves like: polar solvents dissolve polar solutes
- Ionic compounds generally soluble in polar solvents
Ways of Expressing Concentration
- Mass percentage equals (mass of solute / mass of solution) times 100
- Volume percentage equals (volume of solute / volume of solution) times 100
- Molarity equals moles of solute per liter of solution
- Molality equals moles of solute per kilogram of solvent
- Normality equals number of equivalents per liter of solution
Colligative Properties
- Properties depending on number of solute particles, not their identity
- Relative lowering of vapor pressure affects evaporation rate
- Boiling point elevation: solution boils at higher temperature
- Freezing point depression: solution freezes at lower temperature
- Osmotic pressure is pressure needed to prevent osmosis
Ideal and Non-ideal Solutions
- Ideal solution follows Raoult's Law perfectly
- Non-ideal solutions show positive or negative deviations
- Raoult's Law: P equals P0 times X
- Henry's Law applies to dissolved gases
- Real solutions are non-ideal due to intermolecular forces
Key Terms
- Solution: Homogeneous mixture of solute and solvent
- Solubility: Amount of solute that dissolves in solvent at given conditions
- Molarity: Moles of solute per liter of solution
- Colligative Properties: Properties depending on number of dissolved particles, not identity
Frequently Asked Questions
Why does salt dissolve better in hot water than cold water?
Higher temperature increases kinetic energy of water molecules, allowing them to break ionic bonds in salt more effectively. Also, solubility of most ionic compounds increases with temperature.
What is the difference between molarity and molality?
Molarity is moles per liter of solution and depends on temperature. Molality is moles per kilogram of solvent and is independent of temperature, making it more accurate for temperature-dependent calculations.
More 12 Chemistry Revision Notes
🤖 Stuck on any of these? Ask Syllab's free AI Tutor to explain step by step →