Free Colligative Properties MCQs with Answers

1. Osmotic pressure (7) does NOT depend on

• A. Molarity
• B. unoveal gas constant
• C. Temperature
• D. structure of solute particle

Explanation: osmotic pressure does not depend on structure of solute particles but it depend on molarity ,temperature,and solute concentration

2. _ properties depend upon the nature of compound.

• A. Extensive
• B. Intensive
• C. Colligative
• D. Physical

Explanation: The explanation for this question will be added soon.

3. Osmotic pressure of a solution is _ property.

• A. Obligative.
• B. Fractional.
• C. Colligative
• D. Automated.

Explanation: Osmotic pressure is a 'colligative' property, like freezing point depression, which means that it depends on the number of particles in solution but not on their chemical identity

4. The vapor pressure lines for pure as well as solutionsof different concentrations are shown. Which line represents pure water?

• A. 1
• B. 2
• C. 3
• D. 4

Explanation: Pure water (with the highest vapor pressure) will boil at the lowest temperature.Boiling occurs when vapor pressure = external pressure.Since pure water already has a higher vapor pressure, it reaches that point sooner - i.e., at a lower temperature

5. Lowering in vapour pressure is the highest for:

• A. 0.2 M urea
• B. 0.1 M Glucose
• C. 0.1 M MgSO4
• D. 0.1 M BaCl2

Explanation: The higher the vanthoff factor, the greater the lowering of vapor pressure. The highest van der hoff factor is for BaCl2On dissociation, it gives 3 moles of ions (2 chloride and one barium). So the highest lowering of vapor pressure will be for BaCl2.

6. Water has a vapor pressure of 23.75 at 250c what is the vapor pressure of a solution sucrose if its mole fraction is 0.25?

• A. 15.2 torr
• B. 17.8 torr
• C. 23.8 torr
• D. 29.7 torr

Explanation: Mole fraction of the solute = xs = 0.25Pressure of the solvent = PH2O = 23.76 torrFirst, we solve for the mole fraction of the solvent.x(H2O) = 1 - 0.25 = 0.75Now, we can solve for the pressure of the solution:P(sol) = (xH2O)(PH2O)= (0.75) (23.76 torr)P(sol) = 17.82 torrTherefore, the vapor pressure of the solution is 17.82 torr.

7. Pure water freezes at 0 oC and boils at 100 oC at standard conditions. Calcium chloride was added to pure water. What do you expect about its freezing point and boiling point?

• A. No change in its freezing point and boiling point
• B. Freezing point increases and boiling point decreases.
• C. Freezing point increases and boiling point increases
• D. Freezing point decreases and boiling point increases

Explanation: The presence of impurities in a substance lowers the melting point but increases the boiling point of the substance.

8. The osmotic pressure of dilute solution is given by the formula:

• A. π = nRT/V
• B. π = PRT
• C. π = CRT
• D. π = PV=nRT

Explanation: The correct formula for the osmotic pressure of a dilute solution is π = CRT, where:C is the molar concentration of the solute.R is the universal gas constant.T is the absolute temperature.Option A presents the ideal gas law, which is not applicable to osmotic pressure. Option B lacks the concentration term necessary for calculating osmotic pressure. Option D is another form of the ideal gas law, irrelevant to the context of osmotic pressure.

9. The osmotic pressure of dilute solution is given below by relationship:

• A. π = iCRT
• B. π = RCT/M
• C. π = nRT/V
• D. π = PV = nRT

Explanation: The correct relationship for the osmotic pressure of a dilute solution is given by the equation π = RCT/M. This equation shows that osmotic pressure is directly proportional to the temperature (T) and molar concentration (C) of the solute, and inversely proportional to the molar mass (M). The formula accounts for the behavior of the solution as it approaches ideal conditions, where R is the ideal gas constant.Option A is incorrect because it includes the van 't Hoff factor, which is not needed for non-electrolyte dilute solutions. Options C and D are incorrect as they refer to the ideal gas law, which is not applicable for calculating osmotic pressure in solutions.

10. Which of the following solution will have

• A. 1 molar solution of urea
• B. 1 molar solution of glucose
• C. 1 molar solution of sodium chloride
• D. 1 molar solution of magnesium chloride

Explanation: The correct answer is the 1 molar solution of urea. Urea is a non-electrolyte, meaning it does not dissociate into ions in solution. This makes it contribute to solution properties as a single particle per molecule, unlike electrolytes that increase the number of particles by dissociating into ions.Glucose, similar to urea, is a non-electrolyte and does not dissociate, but the question may be looking for the option that contrasts with electrolytes like NaCl and MgCl2. Sodium chloride dissociates into two ions, and magnesium chloride dissociates into three ions, increasing their effective concentration in terms of particle number, thus affecting colligative properties differently.