CBSE Class 12 Chemistry Notes Chapter 2 Solutions PDF Download

CBSE Class 12 Chemistry Notes Chapter 2: CBSE Class 12 Chemistry Notes for Chapter 2 Solutions are important for students studying Chemistry, as mastering the concepts in this chapter is important for understanding various applications in chemistry.

Checkout Class 12th Sample Papers from PW Store

CBSE Class 12 Chemistry Notes Chapter 2 Solutions Overview

CBSE Class 12 Chemistry Notes Chapter 2 PDF

CBSE Class 12 Chemistry Notes Chapter 2 Solutions PDF

CBSE Class 12 Chemistry Notes Chapter 2 Solutions

Solutions

Classification of Solutions:

Based on Physical State:

• Aqueous Solution: If water is the solvent, the solution is called an aqueous solution.
• Non-Aqueous Solution: If the solvent is not water, the solution is termed non-aqueous.

Based on Amount of Solute:

• Unsaturated Solution: This type of solution can dissolve more solute at a given temperature.
• Saturated Solution: In this solution, no more solute can be dissolved at a specific temperature.
• Supersaturated Solution: This contains more solute than what would normally be dissolved at that temperature, often achieved by altering the temperature or pressure.

Solubility

Nature of the Solute: Different solutes have varying degrees of solubility based on their chemical properties and interactions with the solvent.

Nature of the Solvent: The solvent's properties, such as its polarity and ability to interact with the solute, significantly impact solubility.

Temperature: Solubility generally increases with temperature for most solid solutes, but this can vary for different substances.

Pressure: For gases, solubility in a liquid is directly proportional to the pressure of the gas above the liquid, as described by Henry's Law.

Henry’s Law

Applications:

Soft Drinks and Soda Water: Carbon dioxide (CO₂) is added under high pressure to increase its solubility, enhancing the fizz in beverages.

Deep-Sea Diving: To reduce the risk of decompression sickness (the bends), divers breathe a mixture of oxygen and helium. Helium, being less soluble, minimizes the risk of nitrogen bubbles forming in the bloodstream.

High Altitudes: At higher altitudes, the partial pressure of oxygen is lower, resulting in decreased oxygen levels in the blood and leading to conditions like hypoxia or "anoxia," which can affect climbers and travelers at high elevations.

Concentration of Solutions

Dilute Solution: A dilute solution contains a relatively small amount of solute compared to the solvent. In such solutions, the concentration of the solute is low, meaning that there is a high proportion of solvent relative to solute.

Concentrated Solution: A concentrated solution contains a large amount of solute relative to the solvent. In these solutions, the solute concentration is high, meaning that there is a smaller proportion of solvent compared to solute.

Methods of Expressing Concentration of Solutions

Percentage by Weight (w/w%) : This is the ratio of the weight of the solute to the total weight of the solution, multiplied by 100. It indicates how much of the solute is present in 100 grams of solution.

Percentage by Volume (w/V%) : This can refer either to the weight of the solute in 100 mL of solution or the volume of the solute in 100 mL of solution.

Mole Fraction (x) : This is the ratio of the number of moles of a component to the total number of moles of all components in the solution.​

Parts Per Million (ppm) : This measures the amount of solute in one million parts of the solution, useful for trace quantities.

Molarity (M) : This is the number of moles of solute per liter of solution.

Molality (m) : This measures the number of moles of solute per kilogram of solvent.

Normality (N) : This is the number of gram-equivalents of solute per liter of solution.

Formality (F) : This is the number of formula weights of solute per liter of solution.​

Mass Fraction : This represents the mass of a component divided by the total mass of the solution, indicating the proportion of the solute in the solution.

Demal (D) : Represents one mole of solute per liter of solution at 0°C.

Raoult’s Law

P _total = p ₁ ⁰ x ₁ +p ₂ ⁰ x ₂

Ideal Solutions

Types of Deviations from Raoult’s Law

Positive Deviations:

• Characteristics: In a solution with positive deviations, the vapor pressure of the solution is higher than what Raoult’s Law predicts. This occurs because the intermolecular forces between the solute and solvent molecules are weaker than those between the molecules of the pure substances.
• Reason: The weaker solute-solvent interactions lead to higher vapor pressures because the solute molecules disrupt the intermolecular forces between the solvent molecules, making it easier for molecules to escape into the vapor phase.
• Example: A common example is a mixture of acetone and chloroform. The interaction between acetone and chloroform is weaker than the interactions in pure acetone or pure chloroform.

Negative Deviations:

• Characteristics: In a solution with negative deviations, the vapor pressure of the solution is lower than what Raoult’s Law predicts. This happens because the intermolecular forces between the solute and solvent molecules are stronger than those in the pure substances.
• Reason: Stronger solute-solvent interactions result in a lower vapor pressure. The strong interactions between the solute and solvent molecules reduce the number of molecules escaping into the vapor phase.
• Example: A typical example is a solution of water and hydrochloric acid. The strong hydrogen bonding between water molecules and the ionic interactions with HCl lead to lower vapor pressure than expected.

Konowaloff's Rule