Class 12th Chemistry chapter Solutions Notes NCERT Solutions.
Solution is a homogeneous mixture composed of two or more substances.
Solutions and Types of Solutions
1. What is a Solution?
A solution is a homogeneous mixture composed of two or more substances. In a solution, the substance present in the largest quantity is called the solvent, while the substance(s) present in smaller quantities are called solutes.
For example, in a saltwater solution, water is the solvent, and salt is the solute.
2. Types of Solutions
2.1 Based on the State of Solvent
Solutions can be classified into three types based on the physical state of the solvent:
2.1.1 Solid Solutions
- Solute: Solid or liquid
- Solvent: Solid
Example: Brass is a solid solution where zinc (solute) is dissolved in copper (solvent).
2.1.2 Liquid Solutions
- Solute: Solid, liquid, or gas
- Solvent: Liquid
Example: Sugar dissolved in water is a liquid solution where sugar is the solute, and water is the solvent.
2.1.3 Gaseous Solutions
- Solute: Liquid or gas
- Solvent: Gas
Example: Air is a gaseous solution composed of nitrogen (solvent) and other gases like oxygen (solute).
2.2 Based on the Amount of Solute Added
2.2.1 Unsaturated Solution
An unsaturated solution contains less solute than it can dissolve at a given temperature. In this state, more solute can still be dissolved in the solvent.
Example: When you add a small amount of sugar to a glass of water, it easily dissolves. This is an unsaturated solution.
2.2.2 Saturated Solution
A saturated solution contains the maximum amount of solute that can be dissolved in the solvent at a given temperature. Adding more solute will result in undissolved particles.
Example: If you keep adding sugar to a glass of water until no more dissolves and the excess sugar settles at the bottom, it becomes a saturated solution.
2.2.3 Supersaturated Solution
A supersaturated solution contains more solute than can typically be dissolved at a given temperature. This is usually achieved by heating the solution, adding excess solute, and then cooling it.
Example: If you heat water, dissolve a large amount of sugar, and then cool it, the excess sugar remains dissolved. This forms a supersaturated solution.
