QUIZ 8 (sec 1)

Which of the following aqueous solutions whose molal concentrations are equal is preferred to be used in preventing the formation of the snow on the sidewalks in cold countries?

• C₆H₁₂O₆

• NaBr

• CaCl₂

• KNO₃

Hydrogen gas is collected when it is prepared in lab by downward displacement of water, the pressure produced on the surface of water is the sum of the pressure of hydrogen gas and the pressure of …………

• Oxygen gas

• Water vapour.

• Hydrogen dissolved in water.

• The noble gases found in air.

Boiling point of one mole of water changes by 0.5°C on dissolving one mole of the ions of the solute in it, what is the boiling point of the molal solution of potassium phosphate?

• 100.5°C

• 99.5°C

• 98°C

• 102°C

In a closed system, a constant vapor pressure results from the formation of a dynamic equilibrium between the vapor and the liquid. At this equilibrium, which two opposing processes are occurring at the same rate?

a) The diffusion of the liquid and the effusion of the vapor

b) The evaporation of the liquid and the diffusion of the vapor

c) The evaporation of the liquid and the condensation of the vapor

d) The self-ionization of water and the condensation of the vapor

e) The breaking of chemical bonds and the formation of chemical bonds

• The diffusion of the liquid and the effusion of the vapor

• The evaporation of the liquid and the diffusion of the vapor

• The evaporation of the liquid and the condensation of the vapor

• The breaking of chemical bonds and the formation of chemical bonds

What is the freezing point of a solution consisting of 426 g of NaSO24 dissolved in 1 L of water?

[H=1g/mol, O=16g/mol, Na=23g/mol, S=32g/mol]

a) −16.74^∘C

b) 1.86^∘C

c) −5.58^∘C

d) 16.74^∘C

• 16.74^∘C

• −5.58^∘C

• 1.86^∘C

• −16.74^∘C

Which of the following solutions would you expect to have the lowest vapor pressure? Assume all solutions are at the same temperature.

• 0.2 M solution of urea

• 0.2 M solution of MgSO₄

• 0.2 M solution of KCl

• 0.2 M solution of AlCl₃

When the two substances (A) and (B) are added to water, each individually, two solutions are formed which have the same boiling point… what is the choice which represents these two solutions?

• 0.1 m sodium carbonate and 0.2 m calcium nitrate.

• 0.1 m sodium carbonate and 0.1 m calcium nitrate.

• 0.1 m potassium nitrate and 0.2 m calcium nitrate

• 0.1 m potassium nitrate and 0.1 m calcium nitrate

Colligative properties of any solution depend only on the concentration of solute particles per unit volume of the solvent. Which of the following is not considered an example of colligative properties?

• Increasing the boiling point of the solution compared to the pure solvent

• Decreasing the vapour pressure of the solution compared to the pure solvent

• Decreasing the freezing point of the solution compared to the pure solvent

• Increasing the viscosity of the solution compared to the pure solvent

Which of the following solutions, which are equally concentrated, has lower vapour pressure?

• Acetic acid solution.

• Potassium chloride solution.

• Sodium phosphate solution.

• Sodium sulphate solution.

Among the following compounds, which one has the lowest freezing point after being dissolved in water, assuming that all of them form equally concentrated solutions?

• Al₃(PO₄)₂

• Na₂SO₄

• Mg(NO₃)₂

• CH₃COOH