- A solution is a homogeneous mixture of two or more substances, with a solvent and solute. Concentrated solutions have more solute, dilute solutions more solvent. - Factors like temperature, pressure, and the nature of solute and solvent affect solubility. Henry's law and Raoult's law describe gas solubility. - Colligative properties like boiling point elevation, freezing point depression, and osmotic pressure depend only on the number of solute particles regardless of identity.

1. SOLUTIONS
-renuha

2. -A solution is a homogenous mixture of two or more pure substances.
-A solution is made up of 2 constituents : solute and a solvent
Solvent : constituent of more composition
Solute: constituent of lesser composition
The term homogeneous mixtures signifies that
both composition and properties are uniform
throughout the mixture.

3. A solution with large quantity of solute : concentrated solution
A solution with large quantity of solvent : dilute solution

4. Mass percentage

5. Volume percentage

6. Mass by volume percentage

7. Parts per million
○ Parts per million : the ratio of number of parts of the component to the total number of
parts of all components of the solution multiplied by 106
.

8. Mole fraction
○ Mole fraction can be defined as the ratio of number of moles of the component in the
solution to the total number of moles of all components in the solution.

9. Molarity [M]
○ Molarity (M) can be defined as the ratio of number of moles of solute to the volume of
solution in liter.
○ It is function of temperature due to the dependence of volume on temperature whereas Mass
%, ppm, mole fraction and molality are independent of temperature because mass does not
depend on temperature.
Si unit: mol L–1. The molarity of a resulting
solution is given

10. Molality [m]
○ Molality (m) can be defined as the ratio of number of moles of solute to the mass of solvent
in kg.
Si unit: mol kg–1.

11. QUESTION
Opt: b
So, the mass of solvent (i.e. water) is less than 1000gram in molar solution. Therefore
one molar aqueous solution contains one mole of solute in less than 1000gram of
solvent whereas one molal solution has one mole of solute in 1000 gram of solvent.

12. solubility
Solubility is a physical property of a solution.
It can be defined as the measure of maximum amount of solute that can be dissolved in a given
amount of solvent.
depends on the nature of solvent and solute ,temperature and pressure

13. Factors affecting solubility of a solid in a liquid :
Nature of solute and solvent : Polar solutes dissolve in polar solvents and non-polar solutes in non-polar solvents. (i.e., like dissolves like).
Effect of temperature :
≫ If the dissolution process is endothermic (ΔsolH > 0), the solubility increases with rise in temperature.
Wg: powdered sugar in hot water dissolves fastest in room temp
≫ If dissolution process is exothermic (ΔsolH < 0), the solubility decreases with rise in temperature.
Effect of pressure : Pressure does not have any significant effect on solubility of solids in liquids as these are highly incompressible.
Maximum amount of a solid solute that can be dissolved in a specified amount of a given liquid solvent does not depend upon pressure
Hexane is not water soluble

14. Factors affecting solubility of a gas in a liquid :
Effect of pressure : Henry’s law states that “the partial pressure of the gas in vapour phase (p) is proportional to the mole fraction of the gas
(x) in the solution”
≫ Higher the value of KH at a given pressure, the lower is the solubility of the gas in the liquid.
Effect of temperature : As dissolution is an exothermic process, then according to Le Chatelier’s principle, the solubility should decrease
with increase of temperature.
○ The phenomenon of increase in the concentration of solution due to dissolving of solid solute to the solvent is known
as dissolution.
○ If added substance dissolves, the solution is unsaturated. If it does not dissolve solution is saturated. If precipitation occurs
solution is supersaturated.
○ The phenomenon of collision of solute particles in a solution resulting in the separation of the solute particles from the
solution is known as crystallization.

15. Henrys law
○ Henry’s law states that “the partial pressure of the gas in vapour phase (p) is proportional
to the mole fraction of the gas (x) in the solution”
○ Henry’s Law establishes a quantitative relation between pressure and solubility of a gas in
a solvent.
○ This law is for gas-liquid solution.
○ According to the law at a constant temperature, the solubility of a gas in a liquid is directly
proportional to the pressure of the gas.
p = KH x where KH = Henry’s law constant.
At same temperature different gases have different KH
Value of Henry’s constant KH increases with increase in temperature.
The value of Henry’s constant KH is greater for gases with lower solubility.
It is a function of the nature of the gas.

16. Applications of henrys law
1.Sealing of soft drink bottles at high pressure increases the solubility of CO2 in soft drinks and soda water.
2.When a diver goes underwater his body is subjected to high pressure. Due to this the body tissues absorbs
more gases. The breathed in oxygen is required for cellular respiration to provide energy to the diver. But the
nitrogen gets absorbed into the body tissues.
The pressure increases with the increase in depth. Therefore as the diver approaches the bottom of the water
body the pressure increases. With this increase in pressure more nitrogen gets absorbed by the body tissues.
But as he approaches upward to come out of the water body the pressure starts decreasing with the decrease in
depth. This in turn decreases the amount of nitrogen getting absorbed by the body tissues.
This causes bubbles of nitrogen in the body which in turn causes bends in the body of the diver.
They are difficult and can even cause threat to their life. To protect the divers ,the water utilized by scuba
jumpers are loaded with diluted air containing 11.7% helium, 56.2% nitrogen and 32.1% oxygen.
3.At high heights the fractional weight of oxygen is not as much as that at the ground level. This
stimulates low concentrations of oxygen in the blood and tissues of individuals living at high
heights or climbers. Low blood oxygen causes climbers to feel feeble and not able to think plainly,
indications of a condition known as anoxia.

17. Roault’s Law
It states that for a solution of two miscible volatile liquids, the partial vapour pressure of each component of
the solution is directly proportional to its mole fraction present in solution. p1 = p1° x1
Vapour pressure: pressure
exerted by vapours above the
liquid surface at a given
temperature.
Raoult's law turns into a unique
instance of Henry’s law
x1 = mole fraction,
pi0 = vapour pressure in
the pure state.
○ Vapour pressure of solution
decreases on addition of a
non-volatile solute to a volatile
solvent.
○ Vapour pressure of a
solvent present in
solution is less than
the vapour pressure of
the pure solvent.

18. Eg: chcl3+acetone and
phenol+aniline ::-ve
Benzene and methanol ,
carbon disulphide-acetone

19. AZEOTROPES
○ Azeotropes are binary mixtures possessing the same composition in fluid, vapor stage and
boiling stage at a steady temperature.
○ The components of azeotropic mixtures are not separated by fractional distillation.
>> Minimum boiling azeotropes : They formed by those liquid pairs which show positive deviations from
ideal behaviour e.g., ethanol-water mixture.
≫ Maximum boiling azeotropes : They are formed by those liquid pairs which show negative deviations
from ideal behaviour e.g., nitric acid-water mixture.

20. These properties of solution depend on the number of solute particles present in the solution
regardless of their nature relative to the total number of particles present in the solution.
1. Relative lowering of vapour pressure of the solvent
2. Depression of freezing point of the solvent
3. Elevation of boiling point of the solvent
4. Osmotic pressure of the solution.
COLLIGATIVE PROPERTIES

21. RLVP
Relative lowering of vapour pressure : When a nonvolatile solute is dissolved in a solvent, vapour pressure
of the solution is lower than that of the pure solvent which is known as lowering of vapour pressure. Relative
lowering of vapour pressure is equal to the mole fraction of the solute in the solution. Relative lowering of
vapour pressure, is a dimensionless quantity.
Occurs only when a non volatile solute is added to a volatile solvent
w1 and M1 = Masses and molar masses of solvent.
w2 and M2 = Masses and molar masses of solute.

22. Depression in freezing point : The freezing point of a solution containing a non-volatile solute is always
less than the freezing point of the pure solvent. This decrease in freezing point is termed as depression in
freezing point.
Note: The molal depression constant is a characteristic property of the solvent. It has nothing to do with solute conc
○ Freezing point of a substance is the temperature at which the vapour pressure
of the substance in its liquid phase is equal to the vapour pressure in the solid phase.
If the vapour pressure of the solution is equal to the vapour pressure of the pure solid solvent then
the solution freezes ○ ΔTf = Tf – Tf0. This is known as depression in freezing
point.
Tf0 = freezing point of pure solvent
Tf0 = freezing point when non-volatile solute is dissolved
Kf is known as freezing point
depression constant or molal
depression constant or Cryoscopic
constant, having unit K kg mol–1.
-Sprinkling of salt helps in clearing the snow covered roads in hills. The
phenomenon involved in the process is dfp

23. ○ A liquid boils at a temperature where the vapour pressure is equal to the atmospheric
Elevation in boiling point : The boiling point of a solution containing a non-volatile solute is always higher than
the boiling point of the pure solvent. This increase in boiling point is termed as elevation in boiling point.
Kb is called boiling point elevation constant or molal elevation constant
or Ebullioscopic constant, having unit K kg mol–1.
○ ΔTb = Tb – Tb0. This is
known as elevation of boiling
point.
Tb0 = boiling point of pure
solvent
Tb0 = boiling point of solution
ELEVATION OF BOILING POINT

24. Osmosis and osmotic pressure : The movement of solvent molecules of a pure solvent from lower
concentration to higher concentration of the solution through semipermeable membrane is termed as
osmosis.
a. This flow of solvents to the solution continues until the stage of equilibrium is reached.
○ The hydrostatic pressure which develops on account of osmosis is called osmotic pressure or the
excess pressure that must be applied on the solution to prevent osmosis is called osmotic pressure.
The flow of solvent from dilute solution to the concentrated solution through a semipermeable
membrane is due to the phenomenon of osmosis.

25. Units of atmospheric pressure and osmotic pressure are the same.
At a given temperature, osmotic pressure of a concentrated solution of a substance
(a) is higher than that of a dilute solution
As
c=concentration [directly prop]
the higher the concentration of solution at given temperature the higher will be the osmotic pressure.

26. Opt : c

28. On the basis of osmotic pressure solution can be classified into three broad categories.
1. Isotonic solutions : Two solutions possessing same osmotic pressure at a given
temperature.
a. No osmosis occurs on isolation of these solutions
2.Hypertonic solutions : solution with higher osmotic pressure or higher concentration of solutes
compared to another solution.
a. the cell will lose water by osmosis and thus shrinks
3.Hypotonic solutions : solution with lower osmotic pressure ., having less solute and more water than
other solution. implying that the outside solution is extremely weaken, the cell will pick up water by
osmosis cell is prone to swell up.

29. -Movement of water from soil to the top of the tree is also due to the phenomenon of osmosis.
○ Due to this reason people consuming more salty food suffer from water retention in their
cell tissues and intercellular spaces resulting in swelling. This is known as edema.

30. Reverse osmosis
○ When a pressure more than the osmotic pressure is applied on the side of the solution ,
pure solvent flows out from the solution through the semi permeable mem this is reverse
osmosis .But reverse osmosis takes place only when external energy is applied to the
more saline solution.
○ In reverse osmosis, solvent molecules move through a semipermeable
○ membrane from higher concentration of solute to lower concentration.
○ Application of larger osmotic pressure to the solution side reverses the direction of
osmosis.
○ Reverse osmosis is extensively used in desalination of sea water