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Solubility of solute

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. Solubility is the maximum weight of a solute that can be dissolved in 100g of a solvent at a given temperature and pressure.

Solubility of solute =   Weight of solute in saturated solution   X 100
Weight of solvent in saturated solution

 

Factors Affecting the Solubility of a Solid Solute

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1) Temperature - Solubility of solute increases with temperature

  • Easier to dissolve sugar in hot milk than in cold milk

2) Size of solute particles-smaller the size greater the solubility of solute

  • Easier to dissolve powdered sugar in coffee then granules of sugar

3) Mechanical Stirring-solubility of solute increases with mechanical stirring.

  • Sugar dissolves faster with faster stirring with a spoon or stirrer.

Note: There are exceptions to the above rules, some solutes do exhibit an anomalous behaviour

Let's look at an example of solubility of a solute (solid)

Factors Affecting the Solubility of a Gas in Water

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The solubility of solute in gaseous form is influenced by two important parameters.

1) Temperature - Increase in temperature decreases solubility of solute in gaseous form

  • On heating, gases dissolved in the milk escape making the milk bubble and boil over.

2) Pressure - Increase in pressure increases the solubility of gas

  • Aerated soda bottles contain carbon dioxide gas under pressure.

Better understand the intricacies involved in the solubility of solute concept here


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