Solutions
Types of solutions across gaseous, liquid and solid states, concentration units including mole fraction, molarity, molality and mass percentage, Raoult's law for volatile and non-volatile solutes, Henry's law for gas solubility, ideal and non-ideal solution behaviour, colligative properties including vapour pressure lowering, boiling point elevation, freezing point depression and osmotic pressure, and abnormal molar masses due to association and dissociation
Topics
Types of Solutions
What solutions are, how solvent and solute roles are assigned, what binary solutions mean, and the nine types of solutions that form when gases, liquids, and solids combine, with everyday and scientific examples for each
Expressing Concentration of Solutions
The seven standard ways to describe how much solute is present in a solution: mass percentage, volume percentage, mass by volume percentage, parts per million, mole fraction, molarity, and molality, with fully worked NCERT examples and a clear comparison of which units depend on temperature
Solubility
What solubility means, why some solids dissolve in certain liquids but not others (the like dissolves like principle), how dissolution and crystallisation reach dynamic equilibrium to form saturated solutions, and how temperature and pressure affect the solubility of solids in liquids
Henry's Law and the Solubility of Gases in Liquids
How pressure and temperature control the amount of gas that dissolves in a liquid, the quantitative relationship given by Henry's law, the meaning and use of the Henry's law constant, and real-world applications including carbonated drinks, scuba diving (bends), and high-altitude sickness (anoxia)
Vapour Pressure of Liquid-Liquid Solutions
Raoult's law for volatile liquid mixtures, deriving the total vapour pressure from partial pressures and mole fractions, Dalton's law applied to solutions, interpreting the linear vapour pressure vs composition graph, determining vapour phase composition, and a fully worked example with chloroform and dichloromethane
Vapour Pressure Lowering by Non-Volatile Solutes
How Raoult's law is a special case of Henry's law, why dissolving a non-volatile solute lowers the solvent's vapour pressure, the molecular-level mechanism behind vapour pressure reduction, Raoult's law for solid-in-liquid solutions, and the linear relationship between vapour pressure and mole fraction
Ideal and Non-Ideal Solutions
What makes a solution ideal or non-ideal, how intermolecular forces determine whether a solution obeys or deviates from Raoult's law, positive and negative deviations with molecular explanations and examples, and azeotropes as the extreme consequence of large deviations
Colligative Properties and Relative Lowering of Vapour Pressure
What colligative properties are, why they depend only on the number of solute particles and not their chemical identity, the four colligative properties of solutions, deriving the formula for relative lowering of vapour pressure, connecting it to mole fraction and molar mass, and a fully worked example calculating molar mass from vapour pressure data
Elevation of Boiling Point
Why adding a non-volatile solute raises the boiling point of a solvent, the relationship between boiling point elevation and molality, the molal elevation constant (ebullioscopic constant), deriving the molar mass formula from boiling point data, and fully worked NCERT examples on glucose in water and molar mass determination from benzene boiling point data
Depression of Freezing Point
How and why dissolving a non-volatile solute lowers the freezing point of a solvent, the vapour pressure explanation using solid-liquid-solution phase curves, the proportionality between freezing point depression and molality, the cryoscopic constant and its units, deriving the molar mass formula from freezing point data, thermodynamic expressions for cryoscopic and ebullioscopic constants, the Table 1.3 data for common solvents, and fully worked NCERT examples on ethylene glycol in water and molar mass determination from benzene freezing point data
Osmosis, Osmotic Pressure, and Reverse Osmosis
How solvent molecules move through semipermeable membranes from dilute to concentrated solutions, the definition and measurement of osmotic pressure, the Van't Hoff equation linking osmotic pressure to molarity and temperature, determining molar masses of proteins and polymers via osmotic pressure, isotonic, hypertonic and hypotonic solutions and their effects on living cells, real-world osmosis in pickles, blood cells, plant water transport and food preservation, reverse osmosis as a water purification technique for desalination, and a fully worked NCERT example on protein molar mass calculation
Abnormal Molar Masses and the Van't Hoff Factor
Why experimentally measured molar masses sometimes disagree with known values, the role of solute dissociation and association in producing abnormal results, the Van't Hoff factor i and its three equivalent definitions, how the factor modifies all four colligative property equations, Table 1.4 data showing i values for NaCl, KCl, MgSO4 and K2SO4 at different concentrations, and fully worked NCERT examples on percentage association of benzoic acid in benzene and dissociation constant of acetic acid in water