Question

The table given below shows number of grams of different solids in 100 g of the solvents - water, alcohol and chloroform (all at 20°C).
(a) Which solid dissolves best in water at 20°C ?
(b) Which solid is maximum soluble in alcohol ?
(c) Which solid is soluble in all the three solvents ?
(d) What is saturated solution ? How can a saturated solution be made unsaturated ?

CBSE Class IX Science SA 2 (3 Marks)

Answer 1

Answer:

A) Sugar

B) Iodine

C) Iodine

D) At any particular temp., a solution that has desolved as much solute as it is capable of dissolving is known as a Saturated Solution.

We can heat to make a saturated solution an unsaturated one.

Hope it helps!!!

Answer 2

Solubility refers to the degree to which a substance (solute) is dissolved in a given solvent to give a solution.

• For a solute to be soluble in a solvent, both the components should have similar kind of intermolecular attraction.
• Sugar dissolves best in water at 20⁰C. The oxygen-hydrogen bonds in sugar are slightly polar in nature, and the polar water molecules attract these charged areas of sugar to dissolve it, forming a clear solution.
• Iodine is very highly soluble in alcohol. Since iodine is a non-polar molecule, it is not very easily dissolved in water. Ethanol, on the other hand is less polar than water and hence dissolves iodine easily. Even chloroform is a non-polar solvent which dissolves iodine.
• Iodine can also dissolve in water in the iodide form. When an iodine molecule reacts with an iodine ion, it forms a a triiodide which is polar and hence dissolves in water.
• A saturated solution is one which has maximum amount of solute dissolved in the solvent and cannot dissolve any more solute. It can be made saturated by adding more solvent.