Solutions

The vapor pressure of pure benzene and methyl benzene at 27 C is given as 80 Torr and 24 Torr, respectively. The mole fraction of methyl benzene in vapor phase, in equilibrium with an equimolar mixture of those two liquids (ideal solution) at the same temperature is 10-2 (nearest integer)

A solution containing 10 g of an electrolyte AB2 in 100 g of water boils at 100.52°C. The degree of ionization of the electrolyte ( ) is 10-1. (nearest integer) [Given : Molar mass of AB2 = 200 g mol-1, Kb (molal boiling point elevation const. of water) = 0.52 K kg mol-1, boiling point of water = 100°C; AB2 ionises as AB2 A2+ + 2B-]

A solution is prepared by adding 1 mole ethyl alcohol in 9 mole water. The mass percent of solute in the solution is (Integer answer) (Given : Molar mass in g mol-1 Ethyl alcohol : 46 water : 18)

Molality of an aqueous solution of urea is 4.44 m. Mole fraction of urea in solution is x 10-3, Value of x is . (Integer answer)

Consider the dissociation of the weak acid HX as given below HX(aq) H+(aq) + X-(aq), Ka = 1.2 10-5 [Ka : dissociation constant] The osmotic pressure of 0.03 M aqueous solution of HX at 300 K is 10-2 bar (nearest integer). [Given : R = 0.083 L bar mol-1 K-1]

When 'x' 10-2 mL methanol (molar mass = 32 g, density = 0.792 g/cm3) is added to 100 mL water (density = 1 g/cm3), the following diagram is obtained. [figure] x = (nearest integer). [Given : Molal freezing point depression constant of water at 273.15 K is 1.86 K kg mol-1]

An artificial cell is made by encapsulating 0.2 M glucose solution within a semipermeable membrane. The osmotic pressure developed when the artificial cell is placed within a 0.05 M solution of NaCl at 300 K is 10-1 bar. (nearest integer). [Given : R = 0.083 L bar mol-1 K-1] Assume complete dissociation of NaCl

Considering acetic acid dissociates in water, its dissociation constant is 6.25 10-5. If 5 mL of acetic acid is dissolved in 1 litre water, the solution will freeze at -x 10-2 C, provided pure water freezes at 0 C. x = . (Nearest integer) Given : (Kf)water = 1.86 K kg mol-1 density of acetic acid is 1.2 g mL-1. molar mass of water = 18 g mol-1. molar mass of acetic acid = 60 g mol-1. density of water = 1 g cm-3 Acetic acid dissociates as CH3COOH CH3COO + H

2.5 g of a non-volatile, non-electrolyte is dissolved in 100 g of water at 25 . The solution showed a boiling point elevation by 2 . Assuming the solute concentration is negligible with respect to the solvent concentration, the vapor pressure of the resulting aqueous solution is mm of Hg (nearest integer) [Given : Molal boiling point elevation constant of water (Kb) = 0.52 K kg mol-1, 1 atm pressure = 760 mm of Hg, molar mass of water = 18 g mol-1]

2.7 kg of each of water and acetic acid are mixed. The freezing point of the solution will be -x C. Consider the acetic acid does not dimerise in water, nor dissociates in water. x = (nearest integer) [Given: Molar mass of water = 18 g mol-1, acetic acid = 60 g mol-1 Kf H2O : 1.86 K kg mol-1 Kf acetic acid: 3.90 K kg mol-1 freezing point: H2O = 273 K, acetic acid = 290 K]