1) The document discusses key concepts related to solutions including expressing concentration through mole fraction, molarity, and molality. 2) It also discusses solubility and how it is affected by factors like the nature of the solute and solvent, temperature, and pressure. When a solid solute dissolves in a liquid, it reaches a dynamic equilibrium where the concentration remains constant. 3) The document provides examples of how solubility is affected by temperature depending on whether the dissolution process is endothermic or exothermic based on Le Chatelier's principle. Pressure does not significantly impact solubility of solids in liquids.

1. Quality Education For All

2. CLASS 12
CHAPTER 2 - SOLUTIONS

3. RECAP
▪ Expressing concentration of solution
quantitatively
➢ Mole fraction
➢ Molarity
➢ Molality

4. TOPICS
▪ Solubility
▪ Solubility of Solid in Liquid

5. Problem 2: Solution of glucose in water is labelled as 10% w/w,
what would be the molality and mole fraction of each component
in the solution? If the density of solution is 1.2 g mL-1,
then what shall be the molarity of the solution?

8. Solubility
• Like dissolves Like
• Polar and Non-polar molecule
Solute Solvent
Salt/Sugar Water
Oil Water
Naphthalene/
Anthracene
Benzene

9. Solubility
• Maximum amount of the substance that can be dissolved in a
specified amount of solvent at specific temperature and pressure.

10. Factors that determine Solubility
✓ Nature of solute and solvent
✓ Temperature
✓ Pressure

11. Solubility of Solid in Liquid
✓ When a solid solute is added to the solvent, some
solute dissolves and it’s concentration increases in
solution - Dissolution
✓ Some solute particles in solution collide with the solid
solute particles and gets separated out of solution –
Crystallization.

12. Solubility of Solid in Liquid
✓ 2 processes : Dissolution
: Crystallization
✓ Dynamic Equilibrium has reached
✓ At this stage, the concentration of solute in
solution will remain constant under given
condition, i.e. temperature and pressure.

13. Saturated and Unsaturated Solution
✓ Solution where no more solute can dissolve at the
same temperature and pressure – Saturated solution
✓ On the other side when more solute can be
dissolved at same temperature and pressure –
Unsaturated solution.

14. Effect of Temperature on the Solubility of
solid in liquid
✓ follow Le Chateliers principle
✓ If any stress is applied to a reaction mixture
at equilibrium, the net reaction shifts in the
direction that relives the stress.

15. Effect of Temperature on the Solubility of
Solid in Liquid
i) If in nearly applied in saturated solution, the dissolution
process is endothermic (Δsol H > 0), the solubility should
increase with rise in temperature.
ii) If the dissolution process is exothermic (Δsol H < 0)
the solubility should decrease with rise in temperature.

16. Effect of Temperature on the Solubility of S in L
✓ Endothermic process, energy released in bond
breaking is less compared to energy absorbed during
bond breaking.
i) If in nearly applied in saturated solution, the dissolution
process is endothermic (Δsol H > 0), the solubility should
increase with rise in temperature.
✓ Temperature , solubility ,dissolution process is
endothermic

17. Effect of Temperature on the Solubility of S in L
✓ Exothermic process, energy released in bond
forming process is much more compared to energy
absorbed during bond breaking.
ii) If the dissolution process is exothermic (Δsol H < 0)
the solubility should decrease with rise in temperature.
✓ Temperature , solubility ,dissolution process is
exothermic

18. Effect of Pressure on the Solubility of
Solid in Liquid
❑ Pressure does not have significant impact on solubility
of solids in liquids.