Solution

1. Concentration

• Molarity (M):

  • Molarity is the number of moles of solute per liter of solution. It is expressed in mol/L.
  • Formula: M = moles of solute/volume of solution in liters
  • Reference: NCERT Class 11, Chapter 13, Solutions

• Molality (m):

  • Molality is the number of moles of solute per kilogram of solvent. It is expressed in mol/kg.
  • Formula: m = moles of solute/ mass of solvent in kilograms
  • Reference: NCERT Class 11, Chapter 13, Solutions

• Mass percentage (% m/m):

  • Mass percentage represents the mass of solute present in 100 parts by mass of the solution.
  • Formula: % m/m = (mass of solute/ mass of solution) x 100
  • Reference: NCERT Class 11, Chapter 13, Solutions

• Volume percentage (% v/v):

  • Volume percentage represents the volume of solute present in 100 parts by volume of the solution.
  • Formula: % v/v = (volume of solute/ volume of solution) x 100
  • Reference: NCERT Class 11, Chapter 13, Solutions

• Parts per million (ppm):

  • Parts per million represents the number of parts of solute present in 1 million parts of the solution.
  • Formula: ppm = (mass of solute/ mass of solution) x 10^6
  • Reference: NCERT Class 11, Chapter 13, Solutions

• Parts per billion (ppb):

  • Parts per billion represents the number of parts of solute present in 1 billion parts of the solution.
  • Formula: ppb = (mass of solute/ mass of solution) x 10^9
  • Reference: NCERT Class 11, Chapter 13, Solutions

2. Colligative Properties

• Boiling Point Elevation (∆Tb):

  • Boiling point elevation is the increase in the boiling point of a solvent when a non-volatile solute is added to it.
  • Formula: ∆Tb = Kb * m where Kb is the boiling point elevation constant of the solvent and m is the molality of the solution
  • Reference: NCERT Class 11, Chapter 13, Solutions

• Freezing Point Depression (∆Tf):

  • Freezing point depression is the decrease in the freezing point of a solvent when a non-volatile solute is added to it.
  • Formula: ∆Tf = Kf * m where Kf is the freezing point depression constant of the solvent and m is the molality of the solution
  • Reference: NCERT Class 11, Chapter 13, Solutions

• Osmotic Pressure (π):

  • Osmotic pressure is the minimum pressure required to prevent the flow of solvent from a less concentrated solution to a more concentrated solution through a semipermeable membrane.
  • Formula: π = cRT where c is the concentration of the solution in mol/L, R is the universal gas constant, and T is the temperature in Kelvin.
  • Reference: NCERT Class 11, Chapter 13, Solutions

• Vapor Pressure Lowering (∆P):

  • Vapor pressure lowering is the decrease in the vapor pressure of a solvent when a non-volatile solute is added to it.
  • Formula: ∆P = P° - P where P° is the vapor pressure of the pure solvent and P is the vapor pressure of the solution.
  • Reference: NCERT Class 11, Chapter 13, Solutions

3. Solubility

• Factors Affecting Solubility:

  • Nature of solute and solvent
  • Temperature
  • Pressure
  • Presence of other substances

• Solubility Curves:

  • Solubility curves graphically represent the relationship between the solubility of a solute and temperature or pressure.

• Henry’s Law:

  • Henry’s law states that the partial pressure of a gas dissolved in a liquid is proportional to the concentration of the gas in the liquid.
  • Formula: p = k[C] where p is the partial pressure of the gas, k is the Henry’s law constant, and [C] is the concentration of the gas in the liquid.
  • Reference: NCERT Class 12, Chapter 4, Chemical Kinetics

4. Types of Solutions

• Ideal Solutions:

  • Ideal solutions are solutions in which the intermolecular forces between solute-solute, solute-solvent, and solvent-solvent are identical.
  • Ideal solutions obey Raoult’s law.

• Non-ideal Solutions:

  • Non-ideal solutions are solutions in which the intermolecular forces between solute-solute, solute-solvent, and solvent-solvent differ.
  • Non-ideal solutions deviate from Raoult’s law.

• Colligative Behavior of Non-Ideal Solutions:

  • Non-ideal solutions show deviations from ideal behavior in terms of colligative properties such as boiling point elevation, freezing point depression, osmotic pressure, and vapor pressure lowering.

• Van’t Hoff Factor (i):

  • Van’t Hoff factor is a measure of the extent of dissociation or association of a solute in a solution.
  • Formula: i = (observed colligative property)/(calculated colligative property)
  • Reference: NCERT Class 12, Chapter 12, Organic Chemistry

5. Raoult’s Law

• Raoult’s Law for Vapor Pressure:

  • Raoult’s law states that the partial pressure of a component in a liquid solution is directly proportional to its mole fraction in the solution.
  • Formula: pA = p°A * XA where pA is the partial pressure of component A, p°A is the vapor pressure of pure component A, and XA is the mole fraction of component A in the solution.
  • Reference: NCERT Class 11, Chapter 13, Solutions

• Ideal and Non-ideal Solutions:

  • Raoult’s law is strictly applicable only to ideal solutions.
  • Non-ideal solutions deviate from Raoult’s law due to intermolecular interactions.

• Deviations from Raoult’s Law:

  • Positive deviations: when the partial pressure of the component is higher than predicted by Raoult’s law. (For example, a mixture of acetone and chloroform)
  • Negative deviations: when the partial pressure of the component is lower than predicted by Raoult’s law. (For example, a mixture of ethanol and water)

6. Distribution Law (Partition Law)

• Distribution Coefficient (K):

  • Distribution coefficient is the ratio of the concentrations of a solute in two immiscible solvents when it is distributed between them.
  • Formula: K = [solute] in solvent A/[solute] in solvent B
  • Reference: NCERT Class 11, Chapter 13, Solutions

• Applications of Distribution Law:

  • Separation of compounds by extraction
  • Partition chromatography

7. Osmosis and Reverse Osmosis

• Mechanism of Osmosis:

  • Osmosis is the movement of solvent molecules from a region of lower solute concentration to a region of higher solute concentration through a semipermeable membrane.

• Osmotic Pressure:

  • Osmotic pressure is the minimum pressure that needs to be applied to the solution to prevent the flow of solvent through a semipermeable membrane.

• Reverse Osmosis and its Applications:

  • Reverse osmosis is a process in which an external pressure is applied to the solution to force the solvent molecules to flow from a region of higher solute concentration to a region of lower solute concentration through a semipermeable membrane.
  • Applications of reverse osmosis include water purification, desalination of water, and concentration of fruit juices.

8. Ionic Solutions

• Electrolytes and Non-electrolytes:

  • Electrolytes are substances that dissociate into ions when dissolved in water, allowing the solution to conduct electricity.
  • Non-electrolytes are substances that do not dissociate into ions when dissolved in water, resulting in a non-conducting solution.

• Ionization of Salts:

  • Salts dissociate into positively charged cations and negatively charged anions when dissolved in water.
  • The extent of ionization is influenced by factors such as the nature of the salt, the dielectric constant of the solvent, and temperature.

• Degree of Ionization:

  • The degree of ionization is the fraction of the total number of moles of solute that dissociates into ions.
  • It can be expressed as α = (number of moles of solute dissociated/ total number of moles of solute) x 100

• Arrhenius Theory of Electrolytic Dissociation:

  • Arrhenius theory states that when an electrolyte dissolves in water, it undergoes ionization, resulting in the