Solutions &

ColloidsChapter # 10Chemistry XI

FDCMs. Sidra Javed

Phase

A samle of mater having a fixed composition and uniform properties throught is called phase

Solution

A Homogeneous mixture of two or more pure substances which has uniform composition throughout is called solution

Components of solutionsSolute: Part of solution which is dissolved.

Solvent: Part of solution in which dissolved.

Components of solutions

Solution of Gas in Gas

1. Air

2. Oxygen - Acetylene (welding apparatus)

Solution of Gas in Liquid1. Oxygen in water

2. Carbonated Drinks

Solution of Gas in Solids

1.Hydrogen absorbed by Palladium

Solution of Liquid in Gas1. Mist

2. Fog

3. Clouds

Solution of Liquid in Liquid1. Alcohol in water

2. Milk

Solution of Liquid in Solid1. Mercury in silver

2. Butter

3. Cheese

Solution of Solid in Gas1. Dust particles in

smoke

Solution of Solid in Liquid1. Sugar in water

2. Jellies

3. Paints

Solution of Solid in Solid1. Metal alloys

2. Pearls

3. Opals

4. Carbon in Iron (Steel)

Hydrophilic MoleculesMolecules that are completely miscible with water is called hydrophilic molecules

Such molecules can form Hydrogen bonds with water

Examples are: C2H5OH, CH3COOH

Hydrophobic moleculesMolecules that do not dissolve in water is called hydrophobic molecules.

Examples are: Molecules of organic fats & oils, molecules present on surface of a leaf

Nature Of Solution In Liquid Phase1. Completely

miscible liquids

2. Partially miscible liquids

3. Completely immiscible liquids

Completely miscible liquid solutionsLiquids which are miscible in all proportions is completely miscible.

Example: Water - alcohol, benzene - cyclohexane

Completely miscible liquid solutionsSimilar Intermolecular interaction

Hydrogen Bonding (Water & ethanol)

London dispersion forces (Benzene & Cyclohexane)

Partially miscible liquid solutionsLiquids that are soluble to a very small extent is called partially miscible.

Example: Bromine - water, Phenol - water , Aniline- water

Bromine Water Bromine + Water

Immiscible liquid SolutionsLiquid which do not dissolve in any proportions at any temperature is called immiscible.Examples: Water - oil, Water - Benzene , CS2

- Water

Dissolution process

When solute is dissolved in a suitable solvent, dissolution occurs.

The measure of speed of solution is called dissolution rate

Factors affecting Solubility or dissolution rate

1.Particle size

2.Temperature

3.Concentration of solute

4.Stirring

Particle size

When a sugar cube is exposed into water , it dissolves slowly than does same amount of finely granulated sugar.

A sugar cube expose less surface to the water as compared to granulated sugar.

Temperature

By increasing Temperature interaction of solute and solvent molecule increases as a result dissolving rate increases.

Concentration of solution

Higher the concentration of solution, lower rate of dissolution, lower solubility

A Saturated solution can dissolve no more solute

Stirring

Stirring is directly proportional to the dissolving rate because stirring increases exposure of solute to the solvent

Solvation of ionic substances

• Solvent molecules surrounds the solute ions – solvation or hydration (in case of water as solvent)

• Ion-dipole interactions

Solvation of molecular solids• Polar solids dissolves

in polar solvent

• Non polar solids dissolves in non polar solvent

• Dipole-dipole , London dispersion forces, Hydrogen bonding

d+d- polarsolute

HOH

d+d-

HOH

d+d-

HEAT ABSORBED OR EVOLVED DURRING DISSOLVING PROCESS

Durring dissolving process the heat may be absorbed or evolved durring dissolved.

It depends upon three types of interaction.

Solute-solute interaction, solvent-solute interaction, solvent-solvent interaction.

Heat of solution depends upon the heat of solution, heat of hydration, lattice energy.

DAILY LIFE APPLICATION OF HEAT OF SOLUTIONHot and cold packs are commonly use today.

Cold packs are used for treatment of injuries and reduction of swelling.

Hot packs are used for instant warmth for hikers and skiers and treatment of pulled muscles.

End of Lesson