Some substances when exposed to the atmospheric air at ordinary temperature, absorb moisture without changing their physical state. Such substances are called hygroscopic substances.

The number of water molecules found in the crystalline substance is called water of crystallization

Two solutes are dissolved in one solvent. Such kind of solutions which contain three components are called trinary solutions.

Most of the liquids found in human body including blood, lymph and urine are solutions.

Concentration of a solution
= \(\frac{Amount \ of \ the \ solute}{Amount \ of \ solvent }\) x 100
= \(\frac{20}{40}\) x 100
= 50

The process of uniform distribution of solute into solvent is called dissolution.

In a solution, the component which is present in lesser amount (by weight), is called solute and the component, which is present in a larger amount (by weight) is called solvent.

(i) The number of water molecule in blue vitriol is five.
(ii) The hot saturated solution of copper sulphate has no water molecule.
(iii) When cooled the hot saturated solutions gain five molecules of water and it will turn to crystal.

(i) Aquatic animals live more in cold regions.
(ii) More amount of dissolved oxygen is present in the water of cold regions.
(iii) This shows that the solubility of oxygen in water is more at low pressure.

(i) Volume percentage is defined as the percentage by volume of solute (in ml) present in the given volume of the solution.
(ii) Volume Percentage = \(\frac{Volume \ of \ the \ solute}{Volume \ of \ the \ solution \ +\ Volume \ of \ the \ solvent}\) x 100

i) Gas in liquid - CO₂ dissolved in water (Soda water)
ii) Solid in liquid - NaCl dissolved in water
iii) Solid in solid - Copper dissolved in gold (Alloys)
iv) Gas in gas - Mixture of Helium-oxygen gases

(i) A solution must at least be consisting of two components ( a solute and a solvent ).
(ii) Such solution which are made of one solute and one solvent (two components) are called binary solution.
(iii) e.g: On addition copper sulphate crystals to water.

(i) A solution is a homogeneous mixture of two or more substances.
E g: Sea water.
(ii) In a solution, the component present in lesser amount by weight is called a solute.
(iii) The component present in a larger amount by weight is called a solvent.
(iv) Solute + Solvent → Solution

The colloidal solution is an example in which solid acts are the dispersion medium while liquid as the dispersed phase. It is also called gel. Reason for the choice. On pressing butter, liquid drops come out of it leaving behind a solid. This clearly shows the butter is a gel.