Students can go through TS Inter 2nd Year Chemistry Notes 2nd Lesson Solutions will help students in revising the entire concepts quickly.
TS Inter 2nd Year Chemistry Notes 2nd Lesson Solutions
→ A homogeneous mixture of two or more substances whose composition can be varied with certain limits is known as true solution e.g. salt in water, sugar in water, air, alloys etc.
→ Gaseous solutions are those in which solvent is gas, solute may be gas or liquid or solid. Eg:
- Gas in gas : air, mixture of O2 and N2
- Liquid in gas: moisture in air
- Solid in gas : camphor in air.
→ Liquid solutions are those in which solvent is liquid while solute may be gas or liquid or solid. Eg:
- Gas in liquid: aerated water, soda water
- Liquid in liquid : alcohol in water
- Solid in liquid: salt in water, sugar in water.
→ Solid solutions are those in which solvent is solid and solute may be gas or liquid or solid. Eg:
- Gas in liquid: occlusion of H2 in palladium
- Liquid in solid : amalgams (liquid Hg in Zn)
- Solid in solid: Alloys like brass, bronze etc.
→ Mole fraction is the ratio of the number of moles of one component to the total number of moles (solute and solvent) in a binary solution.
→ In a solution, the sum of mole fraction of all components = 1
→ Molarity (M) is the number of moles of solute present in one litre of solution.
→ Normality is the number of gram equivalents of solute present in one litre of solution, represented by ‘N’.
→ Relation between molarity (M) and normality (N) of any solution are related as
Molarity × \(\frac{\text { Molecular Weight }}{\text { Equivalent Weight }}\) = Normality
Molarity = \(\frac{\text { Normality } \times \text { Equivalent Weight }}{\text { Molecular Weight }}\)
→ Henry’s law states that the mass of gas dissolving in a given amount of liquid is directly proportional to the pressure of the gas above the liquid at equilibrium.
m ∝ p or m = k.p (k is constant) k value depends on the nature of the gas, nature of the solvent,.temperature and the units of pressure.
→ Raoult’s states that partial pressure of a component (say liquid A) in solution is proportional to the mole fraction.
→ The decrease in the vapour pressure of a liquid when a non – volatile solute is dissolved in it is called the lowering of vapour pressure.
→ The ratio of the lowering of vapour pressure showing (p – pg) to the vapour pressure of the pure solvent (p) is known as the relative lowering of vapour pressure.
→ Raoult’s law states that the relative lowering of vapour pressure of a dilute solution of a non-volatile solute is equal to the mole fraction of the solute.
\(\frac{p-p_s}{p}=\frac{n}{n+N}\) where n and N are the moles of solute and solvent in a solution.
→ The properties of dilute solutions which depend on the number of particles (ions or molecules) of the solute dissolved in the solution are called colligative properties.
→ Lowering of vapour pressure, elevation of boiling point, depression in freezing point and osmotic pressure are colligative properties.
→ Since vapour pressure of a solution is less than the vapour pressure of pure solvent, the solution boils at a higher temperature than the boiling point of pure solvent and is known as elevation of boiling point.
→ Since the vapour pressure of a solution is less than the vapour pressure of pure solvent, the solution freezes at a lesser temperature than the freezing point of pure solvent and is known as depression in freezing point.
→ The inflow of solvent from a dilute solution into the concentrated solution of the solute when the two solutions are separated by a semipermeable membrane is also called as osmosis.
→ According to vant Hoff, all laws that applicable to gases are also applicable to dilute solutions and these laws are called vant Hoffs laws.
→ Solutions of same osmotic pressure at a given temperature are called isotonic solutions.
→ The molecular weights determined by using colligative properties of substances which associate or dissociate will be abnormal and are called abnormal molecular weights.
→ The ratio of the observed colligative property and calculated colligative property is called vant Hoff factor ‘i’.