Important Questions for CBSE Boards Exams Class 12 Chemistry Chapter 1- The Solid State 2023-24

CBSE Class 12 Chemistry Chapter 1 Important Questions - Free PDF Download 

Important Class 12 Chemistry Chapter 1 Questions are written by the experts at School Notes Wallah. These questions are prepared so that students have a clear understanding of the topics. These also help students revise and practice for upcoming tests. Semiconductor Class 12 important questions are prepared for students to better understand the type of questions they will face in their exam. The questions are accessible both online and offline. You can browse through the notes or practice questions at any time.

Questions:

1.   1.    State Henry’s law. Give its mathematical form.

 Ans: Henry’s law states that at constant temperature, the solubility of a gas in a liquid is directly proportional to the pressure of the gas. Mathematically, p = KH.x (where p is the partial pressure, x is the mole fraction and KH is the Henry’s law constant).

2.     2. Write any two applications of Henry’s law.

Ans: (i) In the preparation of soda water and soft drinks. (ii) A medical condition known as Bends in Scuba divers.

3.    3.   State Raoult’s law.

 Ans: The law states that for a solution of volatile liquids, the partial vapour pressure of each component in the solution is directly proportional to its mole fraction present in solution. Mathematically, P1 = P1 0 x1, P2 = P2 0 x2

4.     4.  . What are ideal solutions? Write any two properties of ideal solutions.

Ans: These are solutions which obey Raoult’s law at all concentrations. For an ideal solution, P1 = P1 0 x1, P2 = P2 0 x2, ∆Hmix = 0 and ∆Vmix = 0

5.     5.  What are azeotropes? Which are the different types of azeotropes?

Ans: They are constant boiling mixtures and have the same composition in liquid and vapour phases. There are 2 types of azeotropes: Maximum boiling azeotropes (E.g. 68% aqueous solution of HNO3 by mass) and Minimum boiling azeotropes (E.g. 95% aqueous solution of ethanol by volume).

6.     6.  What are colligative properties? Name the four types of colligative properties.

Ans: These are properties of dilute solutions, which depend only on the number of solute particles and not on their nature.

The important colligative properties: (i) Relative lowering of Vapour pressure (ii) Elevation of boiling point (iii) Depression of freezing point (iv) Osmotic pressure.

7.     7.  What is osmotic pressure?

 Ans: It is the excess pressure that must be applied on solution side to prevent osmosis.

8.    8.   What is reverse osmosis? Write any one of its applications.

Ans: If a pressure larger than the osmotic pressure is applied to the solution side, the direction of osmosis gets reversed. This phenomenon is called reverse osmosis. It is used in desalination of sea water.

9.    9.   For intravenous injections only solutions with osmotic pressure equal to that of 0.9% NaCl solution is used. Why?

Ans: This is because our blood cells are isotonic with 0.9% (mass/volume) NaCl solution. So osmosis does not occur, if we place the blood cells in this solution.

. 10.  For determining the molecular mass of polymers, osmotic pressure is preferred to other properties. Why?

Ans: This is because the magnitude of osmotic pressure is large even for very dilute solutions.

11.What are isotonic solutions?

 Ans: Two solutions having same osmotic pressure are called isotonic solutions.

12. Write any 2 advantages of osmotic pressure measurement over other colligative property measurements?

Ans: (i) Osmotic pressure measurement can be done at room temperature. (ii) Here molarity of the solution is used instead of molality, which can be determined easily.