Q1. Differentiate between molarity and molality of a solution.
Q2. Define the following terms:
• Mole fraction
• Normality
_1663498823627.JPEG)
Q3. State Henry’s law and mention two of its important applications.
Q4. Define the following terms:
• Dissolution
• Crystallisation
• Solubility
Q5. Why do gases nearly always tend to be less soluble in liquids as the temperature is raised?
Q6. Given a solution of HNO3 of density 1.4 g/mL and 63% w/w. Determine the molarity of HNO3 solution.
Q7. What is the molarity of solution if the density of a solution prepared by dissolving 120 g of urea (mol. mass =60 u) in 1000 g of water is 1.15 g/ml.
Q8. Why do we prefer to measure the concentrations of solution in molality over molarity?
Q9.State Raoult’s law.
Q10. Explain why aquatic species are more comfortable in cold water rather than in warm water.
Q11. Non-ideal solutions exhibit either positive or negative deviations from Raoult’s law. What are these deviations and why are they caused? Explain with one example for each type.
Q12. Differentiate between Ideal and Non-ideal solutions.
Q13. Why do gases nearly always tend to be less soluble in liquids as the temperature is raised?
Q14. Write a Short note on Azeotropes.
Q15. On mixing liquid X and liquid Y, volume of the resulting solution decreases. What type of deviation from Raoult’s law is shown by the resulting solution? What change in temperature would you observe after mixing liquids X and Y?
Q16. Gas (A) is more soluble in water than Gas (B) at the same temperature. Which one of the two gases will have the higher value of KH (Henry’s constant) and why?
Q17. In non-ideal solution, what type of deviation shows the formation of maximum boiling azeotropes?
Q18. If N2 gas is bubbled through water at 293K, how many millimoles of N2 gas would dissolve in 1 litre of water? Assume that N2 exerts a partial pressure of 0.987 bar. Given that Henry’s law constant for N2 at 293K is 76.48 k bar.
Q19. Benzene and Toluene form a ideal solution over a entire range of composition. The vapour pressure of pure benzene and toluene at 300 K are 50.71 mmHg and 32.06 mmHg respectively. What will be the mole fraction of benzene in vapour phase if 80 gm of benzene is mixed with 100 gm of toluene.
Q20. 100gm of liquid A (M.M. =140 gm/mol) was dissolved in 1000gm of liquid B (M.M. = 180 gm/mol). The vapour pressure of pure liquid B was found to be 500 torr. If the total vapour pressure of the solution is 475 torr, What would be the vapour pressure of the pure liquid A.
Q21. Define the term colligative properties.
Q22. What do you mean by the ‘Relative lowering of Vapour pressure’?
Q23. A solution containing 30 g of non-volatile solute exactly in 90 g of water has a vapour pressure of 2.8 kPa at 298 K. Further 18 g of water is added to this solution. The new vapour pressure becomes 2.9 kPa at 298 K. Calculate
(i) the molecular mass of solute and
(ii) vapour pressure of water at 298 K.
Q24. A solution is prepared by dissolving 10 g of non-volatile solute in 200 g of water. It has a vapour pressure of 31.84 mm Hg at 308 K. Calculate the molar mass of the solute.[Vapour pressure of pure water at 308 K = 32 mm Hg].
Q25. Calculate the mass of a non-volatile solute (molecular mass 40) which should be dissolved in 114 g octane to reduce the vapour pressure to 80%.
Q26. An aqueous solution of 2 percent non-volatile solute exerts a pressure of 1.004 bar at the boiling point of the solvent. What is the molecular mass of the solute? [Vapour pressure of water = 1.013 bar]
Q27. The vapour pressure of pure liquids A and B at 400 K are 450 and 700 mmHg respectively. Find out the composition of liquid mixture if total vapour pressure at this temperature is 600 mmHg.
Q28. What do you mean by relative lowering of vapour pressure?
Q29. What do you understand by Elevation in boiling point?
Q30. Define Colligative properties.
Q31. Out of 0.1 molal aqueous solution of glucose and 0.1 molal aqueous solution of KCI, which one will have higher boiling point and why?
Q32. 30 g of urea [M = 60 g mol-1] is dissolved in 846 g of water. Calculate the vapour pressure of water for this solution if vapour pressure of pure water at 298 K is 23.8 mm Hg.
Q33.A solution of glycerol (C3H8O3) in water was prepared by dissolving some glycerol in 500 g of water. This solution has a boiling point of 100.42°C while pure water boils at 100°C. What mass of glycerol was dissolved to make the solution? [Kb for water = 0.512 K kg mol-1].
Q34. Urea forms an ideal solution in water. Determine the vapour pressure of an aqueous solution containing 10% by mass of urea at 40°C. (Vapour pressure of water at 40°C =55.3 mm of Hg)
Q35. A solution prepared by dissolving 1.25 g of oil of winter green (methyl salicylate) in 99.0 g of benzene has a boiling point of 80.31°C. Determine the molar mass of this compound. [B.P. of pure benzene = 80.10°C and Kb for benzene = 2.53 °C kg mol-1].
Q36. 18 g of glucose, C6H12O6 [molar mass = 180 g mol-1] is dissolved in 1 kg of water in a sauce pan. At what temperature will this solution boil? [Kb for water = 0.52 K kg mol-1]. [boiling point of pure water = 373.15 K].
Q37. What would be the molar mass of a compound if 6.21 g of it dissolved in 24.0 g of chloroform form a solution tha thas a boiling point of 68.04°C. The boiling point of pure chloroform is 61.7°C and the boiling point elevation constant, Kb, for chloroform is 3.63 °C/m.
Q38. What do you mean by depression in freezing point?
Q39. Define the following:
• Osmosis
• Osmotic Pressure
• Reverse Osmosis
• Isotonic solutions
• Abnormal molar mass
Q40. What mass of ethylene glycol (molar mass = 62.0 g/mol) must be added to 5.50 kg of water to lower the freezing point of water from 0 to –10.0°C. [kf for water = 1.86 K kg mol-1].
Q41. 15.0 g of an unknown molecular material was dissolved in 450 g of water. The resulting solution was found to freeze at –0.34°C. What is the molar mass of this material? [kf for water = 1.86 Kkgmol-1].
Q42. 1.00 g of non-electrolyte solute dissolved in 50gm of benzene lowered the freezing point of benzene by 0.40 K. Find the molar mass of the solute.
Q43. Calculate the amount of KCI which must be added to 1 kg of water so that the freezing point is depressed by 2 K. [Kf for water = 1.86 K kg mol-1].
Q44. Calculate the mass of compound [molar mass = 256 g mol-1] to be dissolved in 75 g of benzene to lower its freezing point by 0.48 K.
Q45. A 4% solution (w/w) of sucrose [M.M. = 342 gm mol-1] in water has a freezing point of 271.15 K. Calculate the freezing point of 5% glucose [M = 180 gm mol-1] in water. [Given: Freezing point of pure water = 273.15 K].