1. Solution and solubility

2. Solution : It is a homogenous mixture of two or more substances(solute and solvent) Homogenous mixture has a uniform composition throughout and the substances in the mixture should not react chemically. In a solution the relative proportion of the solute and the solvent can be varied giving rise to either dilute or concentrated solution. Solute: That substance which dissolves in a medium to produce a solution is called the solute. Solute can be solid,liquids or gases. Eg.NaCl solution, alcohol in water & soda water

3. Solvent It is the medium in which the solute dissolves.

4. List of some common solutes and solvents solutes solvent Iodine Chlorophyll Paraffin wax Sulphur Rust Paint Phosphorus Nail polish Grease Ethyl alcohol Methylated spirit Turpentine oil Carbon disulphide Oxalic acid Turpentine oil Carbon disulphide Acetone petrol

5. Types of solutions Unsaturated solution Saturated solution Supersaturated solution

7. Solubility Solubility at a particular temperature may be defined as the maximum amount of the solute in gram that can be dissolved in 100 grams of the solvent at that temperature at one atmospheric pressure. If w g of a solute dissolves in W g of the solvent to make a saturated solution, then solubility is given by Solubility= mass of the solute/mass of solvent X 100 w/W x 100

8. Factors affecting the solubility of a substance 1.Nature of solute Eg.solubility of KClO3 at O 0 C is 4 gm per 100 g of water whereas the solubility of NaCl is 37 g per 100 g water. 2.Nature of solvent Eg.NaCl is extremely soluble in water, slightly soluble in alcohol and insoluble in benzene. 3.Temperature :in general the S of substance increases with increase of temp. Exception: solubility of slaked lime decreases with temp. Solubility of CaSO4 increases from O 0 C to 4O 0 C and decreases on further heating.

9. Solubility of solid and gases in water solids gases Solubility increases with increase in temp. Solubility is independent of pressure Solubility decreases with increase in temperarure Solubility increases with increase in pressure

10. Solubility Curves The graph between the solubility of a substance and temperature at which such solubility has been determined is called the solubility curve. 1.The X-axis represents the T. 2.The Y-axis represents the solubility of the solute in 100 g of the solvent.

12. To predict whether the solubility will increase or decrease with the rise of temp. If the dissolution of the substance in water results in endothermic reaction then solubility will increase with increase of temp. If the dissolution of the substance in water results in exothermic reaction then solubility will decrease with increase of temp.