Explain saturated solution Pure substance colloid & suspension
4. Explain the following giving examples.
(a) saturated solution
(b) pure substance
(c) colloid
(d) suspension
Answer:
a) Saturated solution:
When we add a solute to the solvent, for example, salt in water, the solute dissolves in the solution. When we add more solute, still the solute dissolves. But after adding the solute continuously, a time comes when solute does not dissolve any more. At this point solute deposit on the bottom of the solvent. We call this stage of the solution as a saturated solution. For example, after adding 36 gm of salt in 100ml water, the water does not dissolve the salt any more. So, 36 gm of salt in 100ml of water is a saturated solution of salt in water.
b) pure substance:
A pure substance is a substance which does not contain any other substances. For example, the water we drink contains traces of minerals and salts, so this water is not pure; but if we boil the water and collect its vapour, the vapour does not contain any mineral and salt, so this water is a pure substance.
c) colloid:
Some particles do not dissolve in a solvent. Such particles are so small that we cannot see them from the naked eye. But these particles scatter the light. We call such a heterogeneous solution of small particles and solvent as a colloid. For example, we cannot see small particles in milk. But we know milk consists of water proteins and fats and calcium. We cannot see these particles, but these particles refract the light.
d) suspension:
Suspension and colloids are similar solutions. The only thing which differentiates between them is the particle size. Particle size in a colloid is small, and we can not see them. But in suspension particles are large enough that we can see them easily through the naked eye.
The solute of both, the colloid and suspension gradually settle at the bottom. In suspension, solute settles fast while in the colloid sink at the bottom slowly.
Example: wheat flour in water; mud in water is a suspension.
Next: Question 5: Soda water, wood, air, soil, vinegar, filtered tea homogeneous or heterogeneous
See also: Question 3 Solubility table.
Explain saturated solution Pure substance colloid & suspension
