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CBSE Important Questions

CBSE Guess > Papers > Important Questions > Class XII > 2008 > Chemistry > Chemistry By Mr. Suneet Mehta

Chemistry

2 Marks questions

Q. 1. Why water from the soil rises to the top of the trees?

Q. 2. Which substance is added to water in car radiators to act as antifreeze?

Q. 3. What is the expected value of Van’t Hoff Factor for K4[Fe(CN)6]?

Q. 4. How is depression in FP related to molecular mass?

Q. 5. Give relation between normality and molarity of i) 1 M H2SO4 ii) 1M Ca(OH)2.

Q. 6. BP of a solution is always________________ than that of pure solvent.

Q. 7. 2 gm each of solute A and B (molar mass A<B) are dissolved separately in 50 gm of solvent. Which will show greater elevation in BP?

Q. 8. Why is CaCl2 used to clear snow on roads?

Q. 9. The boiling points of ethyl alcohol and methyl alcohol are 78.3ºC and 64.5ºC. Which of them has a higher vapour pressure?

Q. 10. What is an azeotrope?

2 Marks questions

Q. 11. Define Osmotic Pressure. Arrange the following in increasing order of OP:

  1. 34.2 g/L of sucrose (MM = 342)
  2. 60 g/L Urea (MM = 60)
  3. 90 g/L glucose (MM = 180) iv) 58.5 gm/L of NaCl (MM = 58.5) (Hint g/L means WB/V)

Q. 12. Define i) Normality ii) Mole Fraction.

Q. 13. Define Roult’s Law.

Q. 14. Define Colligative Property. Show that relative lowering in vapour pressure is equal to mole fraction of solute.

Q. 15. Explain why addition of solute lowers freezing point of sol. Draw the graph also.

3 Marks questions

Q. 16. A commercially available sample of sulphuric acid contains 25% H2SO4 by weight (density = 1.10 g/ml) Calculate

  1. Molarity
  2. Normaility
  3. Molality.

Q. 17. A solution containing 0.5 gm of KCl dissolved in 100 gm of water freezes at -0.240C. Calculate the degree of dissociation of salt. Kf for water = 1.86.

Q. 18. Osmotic Pressure of Blood is 8.21 atm at 370C. How much glucose should be used per litre for an intravenous injection that is isotonic with blood?

5 Marks questions

Q. 19. Define Van’t Hoff Factor. Why do some solutes show abnormal molar masses? Give the value of Van’t Hoff Factor for i) Association ii) Dissociation iii) Non-Electrolytes. How do colligative properties get modified with help of Van’t Hoff Factor. Give equation only.

Q. 20. Define and give characteristics of ideal and non-ideal solutions. With the help of graph and examples explain types of non-ideal solutions.