Saturday, May 6, 2023

Quick revision note of Chapter : Solutions , Chemistry Class 12

 SOLUTIONS

Introduction to Solutions:

- A solution is a homogeneous mixture of two or more substances that are uniformly dispersed at the molecular or atomic level.

- Solutions can exist in all three states of matter: solid, liquid, and gas.

- The solute is the substance being dissolved in the solvent, and the resulting mixture is a single-phase solution.


Types of Solutions:

- Solid solutions have a solid solute and a solid solvent. An example of a solid solution is an alloy.

- Liquid solutions have a liquid solute and a liquid solvent. An example of a liquid solution is sugar dissolved in water.

- Gas solutions have a gas solute and a gas solvent. An example of a gas solution is air.


Solubility and Saturated Solutions:

- Solubility is the maximum amount of solute that can be dissolved in a given amount of solvent at a particular temperature and pressure.

- An unsaturated solution is a solution in which the amount of solute present is less than its solubility.

- A saturated solution is a solution in which the amount of solute present is equal to its solubility.

- A supersaturated solution is a solution in which the amount of solute present is greater than its solubility.


Concentration Units:

- Molarity (M) is the number of moles of solute present in one liter of solution.

- Molality (m) is the number of moles of solute present in one kilogram of solvent.

- Mole fraction (X) is the ratio of the number of moles of solute to the total number of moles of solute and solvent in the solution.

- Percentage composition is the percentage of the mass of the solute in the total mass of the solution.


Solubility and Factors Affecting Solubility:

- Factors that affect solubility include temperature, pressure, and the nature of the solute and solvent.

- Henry's Law states that the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid.


Colligative Properties of Solutions:

- Colligative properties are properties of a solution that depend on the concentration of the solute particles, regardless of the nature of the solute.

- The four colligative properties are vapor pressure lowering, boiling point elevation, freezing point depression, and osmotic pressure.


Ideal and Non-Ideal Solutions:

- Ideal solutions follow Raoult's law, which states that the vapor pressure of each component in an ideal solution is proportional to its mole fraction in the solution.

- Non-ideal solutions deviate from Raoult's law and have activity coefficients that vary from unity.


Abnormal Molar Masses:

- Abnormal molar masses can occur when a solute undergoes association or dissociation in solution.

- The molar mass of a solute can be determined using colligative properties, such as boiling point elevation and freezing point depression.


Osmosis and Osmotic Pressure:

- Osmosis is the movement of solvent molecules across a semi-permeable membrane from a region of low solute concentration to a region of high solute concentration.

- Osmotic pressure is the pressure required to stop the flow of solvent molecules across a semi-permeable membrane.


Applications of Solutions:

- Solutions are used in various applications, including in industry, medicine, and everyday life.

- Some common solutions used in industry include acid-base solutions, metal plating solutions, and electrolytes.

- In medicine, solutions are used as drugs, vaccines, and medical solutions.


These are some of the key concepts and ideas covered in the chapter on Solutions in Chemistry

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