Solution Topic
Solution
1. Concentration
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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Factors Affecting Solubility:
- Nature of solute and solvent
- Temperature
- Pressure
- Presence of other substances
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Solubility Curves:
- Solubility curves graphically represent the relationship between the solubility of a solute and temperature or pressure.
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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
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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.
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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.
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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.
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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
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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
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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.
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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)
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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
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Applications of Distribution Law:
- Separation of compounds by extraction
- Partition chromatography
7. Osmosis and Reverse Osmosis
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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.
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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.
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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
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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.
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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.
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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
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Arrhenius Theory of Electrolytic Dissociation:
- Arrhenius theory states that when an electrolyte dissolves in water, it undergoes ionization, resulting in the