GITARATTAN JINDAL PUBLIC SCHOOL
ROHINI, DELHI-110085
QUESTION BANK
CHAPTER- SOLUTIONS
CLASS
: XII
SUBJECT : CHEMISTRY
Q1.
Differentiate molarity and molality for a reaction. How does change in temperature influence this
value?
Q2.
Calculate the freezing point of an aqueous solution containing 10.5 g of MgBr2 in 200 g of water.
(Molar mass of MgBr2= 184 g) (Kf of H2O = 1.86K kg/mol)
Q3.
Define osmosis and osmotic pressure. Is the osmotic pressure of a solution a colligative property?
Explain. How MB can be determined from osmotic pressure? Calculate the boiling point of a
solution prepared by adding 15 g of NaCl to 250 g of H2O.
Q4.
State Henry’s Law about partial pressure of a gas in a mixture. State Raoult’s Law in its general
form in reference to solution. A solution prepared by dissolving 8.9 mol of a gene fragment in 355
ml of water has an osmotic pressure of 0.335 torr at 25°C. Determine its molar mass. (1 torr=760
atm).
Q5.
What would be the molar mass of a compound if 6.21 g of it is dissolved in 24 g of chloroform
from a solution that has a B.P of 68.04°C? The B.P of pure chloroform is 61.75°C and the boiling
point elevation constant, Kb for chloroform is 3.63°C.
Q6.
Calculate the temperature at which a solution containing 54 g of glucose (C6H12O6) in 250 g of
water will freeze. (Kf =1.86 K Kg/mol)
Q7.
Taking suitable examples explain the meaning of positive and negative deviation from Raoult’s
Law.
Q8.
A solution containing 8 g of substance in 100 g of diethyl ether boils at 36.8°C when ether boils at
35.6°C. Determine molecular mass of the solute. (for ether Kb = 2.02 K Kg/mol)
Q9.
State how the V.P of a solvent is affected when a non volatile solute is dissolved in it. A 5%
solution of cane sugar in water has a freezing point of 271 K. Calculate the freezing point of 5%
solution of glucose in water. The freezing point of pure water is 273.15 K. (Molecular mass of cane
sugar = 342 g, glucose = 180 g)
Q10. If the density of water of a lake is 1.25g/mol and kg of lake water contains 92 g of Na+ ions.
Calculate the molarity of Na+ ions.
Q11. Calculate the mass of a non-volatile solute (molar mass 40 g/mol) which should be dissolved in
114g of octane to reduce its vapour pressure to 80%.
Q12. 100 g of protein is dissolved in water to make 10 ml of solution. If this solution has an osmotic
pressure of 13.3 mm Hg at 25°C. What is the molar mass of the protein?
Q13. Calculate the F.P. depression for 0.071 m aqueous solution of Na2SO4. If this solution actually
freezes at -0.32°C. What would be the value of Van’t Hoff Factor? (Kf=1.86 K Kg/mol)
Q14. Define :a) Mole fraction
b) Isotomic solutions
c) Van’t Hoff Factor
d) Ideal Solution
Q15. A 1.00 molal solution of CCl3COOH is heated to its boiling point. The solution has the boiling
point of 100.18°C. Determine the Van’t Hoff Factor for the acid. (Kb for water = 0.512 K Kg/mol)
Q16. 15 g of an unknown molecular material was dissolved in 450 g of water. The resulting solution was
found to freeze at -0.34. What is the molar mass of this material? (Kf of H2O = 1.86 K Kg/mol)