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| Solutions |
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| Solution is defined as a homogeneous mixture of two or more chemical substances. The state of matter of a solution may be solid, liquid or gaseous. |
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| For example, common salt in water (liquid solution), air (gaseous solution), alloys (solid solution), etc. |
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| The components of a solution may be classified as: |
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 Solute |
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 Solvent |
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| Difference between solute and solvent |
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| Thus, an intimate mixture of solute and solvent is called a solution. |
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| Aqueous solutions |
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| Solutions that contain water as the solvent are called aqueous solutions. |
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| For example, sugar in water, carbon dioxide in water, etc. |
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| Non-aqueous solutions |
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| Solutions that contain a solvent other than water are called non-aqueous solutions. Ether, benzene, petrol, carbon tetrachloride etc., are some common solvents. |
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| For example, sulphur in carbon disulphide, naphthalene in benzene, etc. |
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| Between two solutions, the solute quantity may be relatively more or less. The solution that has a greater proportion of solute is said to be more concentrated than the other that has a lesser proportion. If the proportion of solute is less, the solution is said to be dilute. |
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| Saturated Solution |
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| A solution in which no more solute can be dissolved at a given temperature is called a saturated solution. |
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| Unsaturated solution |
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| A solution in which more solute can be dissolved at a given temperature is called an unsaturated solution. |
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| A given solution that is saturated at a particular temperature may become unsaturated when the temperature is increased. |
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| Solubility is defined as the number of grams of a solute that dissolves in 100g of a solvent to form a saturated solution at a given temperature and pressure. |
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| Solubility is the maximum weight of a solute that can be dissolved in 100g of a solvent at a given temperature and pressure. |
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| Temperature |
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| Increase in temperature increases the solubility. |
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| For example, it is easier to dissolve sugar in hot milk than in cold milk. |
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| Size of solute particles |
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| Smaller the size of the particles greater is the solubility. |
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| For example, it is easier to dissolve powdered sugar than granules of sugar. |
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| Mechanical stirring |
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| Mechanical stirring increases solubility. |
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| For example, sugar dissolves faster on stirring with a spoon. |
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| Temperature |
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| Increase in temperature, decreases the solubility of a solute. On heating, the gases dissolved in milk escape making the milk bubble and boil over. |
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| Pressure |
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| An increase in pressure increases the solubility of a gas. |
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| For example, aerated water bottles contain carbon dioxide gas under pressure. |
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