Q2.1 Define the term solution. How many types of solutions are formed? Write briefly about each type with an example. Solution

Q2.2 Give an example of a solid solution in which the solute is a gas. Solution

Q2.3 Define the following terms :
(i) Mole fraction
(ii) Molality
(iii) Molarity
(iv) Mass percentage. Solution

Q2.4 Concentrated nitric acid used in laboratory work is 68% nitric acid by mass in aqueous solution. What should be the molarity of such a sample of the acid if the density of the solution is 1.504 g mL^-1? Solution

Q2.5 A Solution of glucose in water is labelled as 10% w/w, what would be the molality and mole fraction of each component in the solution? If the density of solution is 1.2 g mL^-1 then what shall be the molarity of the solution? Solution

Q2.6 How many mL of 0.1 M HCl are required to react completely with 1 g mixture of Na₂CO₃ and NaHCO₃ containing equimolar amounts of both? Solution

Q2.7 A solution is obtained by mixing 300 g of 25% solution and 400 g of 40% solution by mass. Calculate the mass percentage of the resulting solution. Solution

Q2.8 An antifreeze solution is prepared from 222.6 g of ethylene glycol (C₂H₆O₂) and 200 g of water. Calculate the molality of the Solution. If the density of the solution is 1.072 g mL^-1. then what shall be the molarity of the solution? Solution

Q2.9 A Sample of drinking water was found to be severely contaminated with chloroform (CHCl₃) Supposed to be a carcinogen. The level of contamination was 15 ppm (by mass):
(i) express this in percent by mass
(ii) determine the molality of chloroform in the water sample
Solution

Q2.10 What does molecular interaction play in a solution of alcohol and water. Solution

Q2.11 Why do gases always tend to be less soluble in liquid as the temperature is raised Solution

Q2.12 State Henry's law and mentioned some important applications. Solution

Q2.13 The partial pressure of ethane over the solution containing 6.53 x 10^-3g of ethane is 1 bar. If the solution contains 5.00 x 10^-2g of ethane then what shall be the partial pressure of the gas? Solution

Q2.14 What is meant by positive and ne gative deviations from Raoult's law and how is the sign of ∆_mixH related to positive and negative deviations from Raoult's law? Solution

Q2.15 An aqueous solution of 2% non-volatile solute exerts a pressure of 1.004 bar at the normal boiling point of the solvent. What is the molar mass of the solute? Solution

Q2.16 Heptane and octane form an ideal sol the two liquid components are 105.2 be the vapour pressure of a mixture ution. At 373 K, the Vapour pressures of kPa and 46.8 kPa respectively. What will of 26.0 g of heptane and 35 g of octane? Solution

Q2.17 The vapour pressure of water is 12.3 kPa at 300 K. Cal culate vapour pressure of 1 molal solution of a non-volatile solute in it. Solution

Q2.18 Calculate the mass of a non-volatile solute (molar mass 40 g mol^-1) which should be dissolved in 114 g octane to reduc € its vapour pressure to 80%. Solution

Q2.19 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 then added to the solution and the new vapour pressure becomes 2.9 kPa at 298 K. Calculate:
(i) molar mass of the solute
(ii) vapour pressure of water at 298 K. Solution

Q2.20 A 5% solution (by mass) of cane sugar in water has freezing point of 271K. Calculate the freezing point of 5% glucose in water if freezing point of pure water is 273.15 K. Solution

Q2.21 Two elements A and B form compounds having formula AB₂ and AB4. When dissolved in 20 g of benzene (C₆H₆). 1 g of AB₂ lowers the freezing point by 2.3 K whereas 1.0 g of AB₄ lowers it by 1.3 K. The molar depression constant for benzene is 5.1 K kg mol^-1. Calculate atomic masses of A and B. Solution

Q2.22 At 300 K, 36 g of glucose present in a litre of its solution has an osmotic pressure of 4.98 bar. If the osmotic pressure of the solution is 1.52 bars at the same temperature, what would be its concentration? Solution

Q2.23 Suggest the most important type of intermolecular attractive interaction in | the following pairs.
(i) n-hexane and n-octane
(ii) I₂ and CCl₄
(iii) NaClO₄, and water
(iv) methanol and acetone
(v) acetonitrile (CH₃CN) and acetone (C₃H₆O).
Solution

Q2.24 Based on solute-solvent interactions, arrange the following in order of increasing A solubility in n-octane and explain. Cyclohexane, KCl , CH₃OH, CH₃CN. Solution

Q2.25 Amongst the following compounds, identify which are insoluble, partially soluble and highly soluble in water?
(i) phenol
(ii) toluene
(iii) formic acid
(iv) ethylene glycol
(v) chloroform
(vi) pentanol. Solution

Q2.26 If the density of some lake water is 1.25g mL^-1 and contains 92 g of Na⁺ ions per kg of water, calculate the molality of Na⁺ ions in the lake. Solution

Q2.27 If the solubility product of CuS is 6 x 10^-16, calculate the maximum molarity of CuS in aqueous solution. Solution

Q2.28 Calculate the mass percentage of aspirin (C₉H₈O₄) in acetonitrile (CH₃CN) when 6.5 g of C₉H₈O₄ is dissolved in 450 g of CH₃CN. Solution

Q2.29 Nalorphene (C₁₉H₂₁NO₃), similar to morphine, is used to combat withdrawal symptoms in narcotic users. Dose of nalorphene generally given is 1.5 mg. Calculate the mass of 1.5 - 10_-3 m aqueous solution required for the above dose. Solution

Q2.30 Calculate the amount of benzoic acid (C₆H₅COOH) required for preparing 250 mL of 0.15 M solution in methanol. Solution

Q2.31 The depression in freezing point of water observed for the same amount of acetic acid, trichloroacetic acid and trifluoroacetic acid increases in the order given above. Explain briefly. Solution

Q2.32 Calculate the depression in the freezing point of water when 10 g of CH₃CH₂CHCICOOH is added to 250 g of water. K_n = 1.4 x 10^-3, K_f = 1.86 K kg mol^-1. Solution

Q2.33 19.5 g of CH₂FCOOH is dissolved in 500 g of water. The depression in the freezing point of water observed is 1⁰C. Calculate the van't Hoff factor and dissociation constant of fluoroacetic acid. Solution

Q2.34 Vapour pressure of water at 293 K is 17.535 mm Hg. Calculate the vapour pressure of water at 293 K when 25 g of glucose is dissolved in 450 g of water. Solution

Q2.35 Henry's law constant for the molality of methane in benzene at 298 K is 4.27 x 10⁵ mm Hg. Calculate the solubility of methane in benzene at 298 K under 760 mm Hg. Solution

Q2.36 100 g of liquid A (molar mass 140 g mol!) was dissolved in 1000 g of liquid B (molar mass 180 g mol^-1). The vapour pressure of pure liquid B was found to be 500 torr. Calculate the vapour pressure of pure liquid A and {ts vapour pressure in the solution if the total vapour pressure of the solution is 475 Torr. Solution

Q2.37 Vapour pressures of pure acetone and chloroform at 328 K are 741.8 mm Hg and 632.8 mm Hg respectively. Assuming that they form Ideal solution over the entire range of composition. Plot p_total, p_chloroform and p_acetone as a function of x_acetone The experimental data observed for different compositions of mixture is:

Plot this data also on the same graph paper. Indicate whether it has positive deviation or negative deviation from the ideal solution. Solution

Q2.38 Benzene and toluene form ideal solution over the entire range of composition. The vapour pressure of pure benzene and toluene at 300 K are 50.71 mm Hg and 32.06 mm Hg respectively. Calculate the mole fraction of benzene in vapour phase if 80 g of benzene is mixed with 100 g of toluene. Solution

Q2.39 The air is a mixture of a number of gases. The major components are oxygen and nitrogen with approximate proportion of 20% is to 79% by volume at 298 K. The water is in equilibrium with air at a pressure of 10 atm. At 298 K if the Henry's law constants for oxygen and nitrogen at 298 K are 3.30 x 10⁷ mm and 6.51 x 107 mm respectively, calculate the composition of these gases in water. Solution

Q2.40 Determine the amount of CaCl₂ (i = 2.47) dissolved in 2.5 litre of water such that its osmotic pressure is 0.75 atm at 27° C. Solution

Q2.41 Determine the osmotic pressure of a solution prepared by dissolving 25 mg of K₂SO₄ in 2 litre of water at 25° C, assuming that it is completely dissociated. Solution