Take a beaker and half fill it with water. Add a teaspoonful of sugar in it. Stir the sugar with a glass rod.
After sometimes you will see that the sugar dissolves in the water. The sugar is said to have dissolved in water, producing a clear liquid called ‘Solution’.
The sugar or other solid that dissolve is known as the “Solute”. The water or other liquid in which the solid dissolves, is known as the “Solvent”.
Solutions of substances in water are known as “Aqueous Solution”. Solute can either be solid, liquid or gas while the solvent is usually a liquid.
TYPES OF SOLUTIONS:
Solid, liquid and Gas may combine with one another to form solutions. Therefore solution may be cassified into the following types.
(1) GAS INTO GAS:
Example: “Air” which is the mixture of oxygen, Nitrogen, Carbon dioxide, rare gasses, and water and dust particles.
(2) GAS INTO LIQUID:
Example: Soft drinks which is the mixture of carbon dioxide in water.
(3) GAS INTO SOLID:
Example: Hydrogen in Palladium.
(4) LIQUID INTO GAS:
Example: Water vapor in air.
(5) LIQUID INTO LIQUID:
Example: Alcohol in water.
(6) LIQUID INTO SOLID:
Example: Sodium amalgam i.e. Hg + Na.
(7) SOLID INTO GAS:
Example: Smoke i.e. Carbon particles in air.
(8) SOLID INTO LIQUID:
Example: Sugar or salt in water.
(9) SOLID INTO SOLID:
Example: Alloy of copper i.e. Brass which is the mixture of copper and zinc.
Water kerosene oil and sprit are different solvents. In these solvents water is the best solvent
Aqueous solutions play an important function in most living things.
(1) The Transport of food and oxygen and the removal of carbon dioxide and other waste products from our bodies occurs through aqueous systems.
(2) Water and aqueous solution are key components of environment, agriculture, industrial processes and our everyday life.
Very few substances are dissolved in either the kerosene oil, and lodine dissolves in the sprit.
QUANTITY OF SOLUTE IN A SOLUTION:
(1) SATURATED SOLUTION:
Take some water in a beaker and add sugar in a small amounts at intervals with constant stirring, till more quantity if added, remains insoluble. The insoluble sugar will settles at the bottom of the beaker, at room temperature and water is incapable to dissolve more sugar. Such a solution is known as saturated solution or in other words.
(2) UNSATURATED SOLUTION:
If the saturated solution is heated you will see that the sugar which settled at the bottom of the beaker begins to dissolve. If you put some more sugar in the hot solution it will also dissolve.
Thus a solution which can dissolve more solute in it at a particular temperature is called an unsaturated solution.
(3) SUPER SATURATED SOLUTION:
Such a solution contains more solid than is required to saturate it at the lower temperature.
Crystal is a solid which possess as a such definite geometrical shape and the process by which these crystals are prepared is called “Crystallization”. A Crystal has fixed angles between its faces, and the faces have sharply defined edges. The process of crystallization helps us to prepare a pure substance.