CHAPTER 01: SOLUTIONS

2001 – Set I
Q1. What do you understand by colligative properties? Write them.
[3 Marks]
Q2.
(a) Show graphically that the freezing point of a liquid is depressed when a non-volatile solute is
dissolved in it.
[2 Marks]
(b) The freezing point of a solution containing 0.3 g of acetic acid in 30.0 g of benzene is
lowered by 0.45°C. Calculate the Van’t Hoff factor. (Kf for benzene = 5.12 K kg mol⁻¹)
[3 Marks]
Q3. One litre aqueous solution of sucrose (M = 342 g mol⁻¹) weighing 1015 g is found to have
an osmotic pressure of 4.82 atm at 293 K. What is the molarity of the sucrose solution?
(R = 0.0821 atm L mol⁻¹ K⁻¹)
[3 Marks]

2001 – Set II
Q1.
(a) Show graphically how the vapour pressure of a solvent and a solution of a non-volatile solute
change with temperature. Show the boiling points of both. Which is higher and why?
[2 Marks]
(b) A solution containing 3.00 g of BaCl₂ in 250 g of water boils at 100.083°C. Calculate the
Van’t Hoff factor and molality of BaCl₂.
(Kb for water = 0.52 K kg mol⁻¹, Molar mass of BaCl₂ = 208.3 g mol⁻¹)
[3 Marks]

2002
Q1. Calculate the number of moles of methanol in 5 L of its 2 M solution. If the density of the
solution is 0.981 kg/L, (M = 32.0 g mol⁻¹)
[2 Marks]
Q2. Explain, with a suitable diagram and example, why some non-ideal solutions show negative
deviations.
[3 Marks]
 2003 – Set I
Q1. An aqueous solution containing 1.248 g of BaCl₂ (M = 208.34 g mol⁻¹) in 100 g of water
boils at 100.0832°C. Calculate the degree of dissociation of BaCl₂.
(Kb for water = 0.52 K kg mol⁻¹)
[3 Marks]
Q2.
What are ideal and non-ideal solutions? Explain the behavior of ideal solutions with a suitable
diagram.
OR
Assuming complete dissociation, calculate the expected freezing point of a solution prepared by
dissolving 6.00 g of Glauber’s salt (Na₂SO₄·10H₂O) in 0.100 kg of water. (Kf = 1.86 K kg mol⁻¹)
[5 Marks]

2003 – Set II
Q1. What is meant by the Van’t Hoff factor? The osmotic pressure of a 0.0103 molar solution of
an electrolyte is 0.70 atm at 27°C. Calculate the Van’t Hoff factor. (R = 0.0821 L atm mol⁻¹ K⁻¹)
What conclusion do you draw about the molecular state of the solute in the solution?
[5 Marks]

2004
Q1. What is the sum of the mole fractions of all the components in a 3-component system?
[1 Mark]
Q2. Define the following terms:
(i) Mole fraction
(ii) Molarity
[2 Marks]
Q3. Elements A and B form covalent compounds AB₂ and AB₄. When dissolved in 20 g of
benzene:
• 1 g of AB₂ lowers the freezing point by 2.3 K
• 1 g of AB₄ lowers it by 1.3 K
(Kf for benzene = 5.1 K kg mol⁻¹)
Calculate the atomic masses of A and B.
[3 Marks]

2005
Q1. Calculate the molality of a solution containing 20.7 g of K₂CO₃ dissolved in 500 mL of
solution. Assume density = 1 g/mL.
[2 Marks]
Q2. What would be the Van’t Hoff factor for a dilute solution of K₂SO₄ in water?
[1 Mark]
Q3. State Henry’s Law for gas solubility in a liquid. Explain the significance of the Henry’s law
constant (KH).
At the same temperature, hydrogen is more soluble in water than helium. Which has a higher KH
and why?
[3 Marks]

2006
Q1. Define mole fraction.
[1 Mark]
Q2. Define an ideal solution.
[1 Mark]
Q3.
(a) Urea forms an ideal solution in water. Determine the vapour pressure of an aqueous solution
containing 10% urea by mass at 40°C.
(Vapour pressure of water at 40°C = 55.3 mmHg)
[3 Marks]
(b) Why is the freezing point depression of 0.1 M NaCl solution twice that of 0.1 M glucose
solution?
[1 Mark]

2007
Q1. State the condition resulting in reverse osmosis.
[1 Mark]
Q2. A 0.1539 molal aqueous solution of cane sugar (M = 342 g mol⁻¹) has a freezing point of
271 K.
The freezing point of pure water is 273.15 K. What will be the freezing point of an aqueous
solution containing 5 g of glucose (M = 180 g mol⁻¹) per 100 g of solution?
[3 Marks]

2008
Q1. State Raoult’s Law for solutions with volatile liquid components. Using a suitable example,
explain deviations from Raoult’s Law.
[2 Marks]
Q2. Define osmotic pressure. Describe how molecular mass can be determined from osmotic
pressure measurements.
[2 Marks]

2008 – Compartment
Q1. State the law correlating gas pressure and its solubility in a liquid. Mention an application.
Q2. State Raoult’s Law for volatile liquid solutions. Using a suitable example, explain positive
deviation.
Q3. A solution containing 8 g of a substance in 100 g of diethyl ether boils at 36.86°C while pure
ether boils at 35.6°C. Determine the molar mass of the solute.
(Kb = 2.02 K kg mol⁻¹)
Q4. Calculate the temperature at which a solution containing 54 g of glucose in 250 g of water
will freeze.
(Kf = 1.0 K kg mol⁻¹)

2009
Q1.
(a) Define:
(i) Mole fraction
(ii) Van’t Hoff factor
[2 Marks]
(b) 100 mg of a protein is dissolved in enough water to make 10 mL of solution.
If the solution has an osmotic pressure of 13.3 mmHg at 25°C, calculate the molar mass.
(R = 0.0821 L atm mol⁻¹ K⁻¹, 760 mmHg = 1 atm)
[3 Marks]
OR
(a) What do you mean by:
(i) Colligative properties
(ii) Molality of solution
[2 Marks]
(b) What concentration of nitrogen should be present in a glass of water at room temperature
(25°C)?
Total pressure = 1 atm, mole fraction of N₂ in air = 0.78, KH = 8.42 × 10⁻⁷ M/mmHg
[3 Marks]

2010
Q1. Differentiate between molarity and molality.
[1 Mark]
Q2. Define osmosis and osmotic pressure. What is the advantage of using osmotic pressure over
other colligative properties to determine molar masses?
[2 Marks]
Q3. What mass of ethylene glycol (M = 62.0 g/mol) must be added to 5.50 kg of water to lower
its freezing point from 0°C to -10°C?
(Kf = 1.86 K kg mol⁻¹)
[3 Marks]
Q4. 15 g of an unknown solute is dissolved in 450 g of water. The solution freezes at -0.34°C.
What is the molar mass of the solute?
(Kf for water = 2.86 K kg mol⁻¹)
[3 Marks]
Q5. What mass of NaCl (M = 58.5 g/mol) must be dissolved in 65 g of water to lower the
freezing point by 7°C?
(Kf = 1.86 K kg mol⁻¹; Van’t Hoff factor = 1.87)
[3 Marks]

2011
Q1. State the following:
1. Raoult’s Law in general form
2. Henry’s Law for partial pressure of gases in mixtures
Q2. A solution is prepared by dissolving 8.95 mg of a gene fragment in 35 mL of water. The
osmotic pressure is 0.335 torr at 25°C.
Assuming the gene fragment is a non-electrolyte, calculate its molar mass.
Q3. What mass of NaCl must be dissolved in 65.0 g of water to lower the freezing point?
Got it! Continuing from Q4 of your chemistry homework questions, keeping the formatting clean
and consistent with your instructions—no emoji numerals, just normal numbers, but with some
motivating and thematic emojis sprinkled around for engagement.

4. What is meant by reverse osmosis?

 5. Differentiate between molarity and molality values for a solution. What is the effect of
change in temperature on molarity & molality value?

2012
1. Define the following terms:
(i) Mole fraction
(ii) Ideal solution
2. 15.0 g of an unknown molecular material is dissolved in 450 g of water. The resulting
solution freezes at -0.34°C. What is the molar mass of the material?
(Kf for water is 1.86 K·kg/mol)
OR
Explain the following:
1. Henry’s law about dissolution of a gas in a liquid.
2. Boiling point elevation constant for a solvent.
3. 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. What mass of glycerol was
dissolved to make this solution?
(Kb for water is 0.512 K·kg/mol)

2013 SET III

1. (a) State Raoult's law for a solution containing volatile components. How does Raoult's
law become a special case of Henry's law?
(b) 1.00 g of a non-electrolyte solute dissolved in 50 g of benzene by 0.40 K. Find the
molar mass of the solute.
(Kf for benzene is 5.12 K·kg/mol)
OR
Define the following terms:
(i) Ideal solution
(ii) Azeotrope
(iii) Osmotic pressure
2. A solution of glucose (C6H12O6) in water is labeled as 10% by weight. What would be
the molality of the solution?
(Molar mass of glucose is 180 g/mol)
2014
1. (a) Define the following terms:
(i) Molarity
(ii) Molal elevation constant
(b) A solution containing 15 g urea (M = 60) per litre of solution in water has the same osmotic
pressure (isotonic) as a solution of glucose (M = 180) in water. Calculate the mass of glucose
present in one litre of its solution.
OR
2. What type of deviation is shown by a mixture of ethanol and acetone? Give reason.
3. A solution of glucose (M = 180) in water is labeled as 10% by mass. What would be the
molality and molarity of the solution?
(Density of solution is 1.2 g/mL)

2015 (all 3 sets have similar questions)

1. (i) Why are aquatic species more comfortable in cold water than in warm water?
(ii) What happens when we place the blood cell in saline water solution (hypertonic
solution)? Give reason.
2. Vapour pressure of water at 20°C is 17.5 mmHg. Calculate the vapour pressure of water
at 20°C when 15 g of glucose is dissolved in 150 g of water.

2016 (all 3 sets have similar questions)

1. (i) Write the colligative property which is used to find the molecular mass of
macromolecules.
(ii) In non-ideal solutions what type of deviation shows the formation of minimum
boiling azeotropes?
2. Calculate the boiling point of solution when 2 g of Na2SO4 is dissolved in 50 g of water,
assuming Na2SO4 undergoes complete ionization.

2017 (SET I / SET II / SET III)

1. (a) A 10% solution (by mass) of sucrose in water has a freezing point of 269.15 K.
Calculate the freezing point of 10% glucose in water if the freezing point of pure water is
273.15 K.
(Molar mass of sucrose = 342 g/mol and glucose = 180 g/mol)
(b) Define the following terms:
i. Molality (m)
ii. Abnormal molar mass
OR
2. (a) 30 g of urea (M = 60 g/mol) 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
mmHg.
(b) Write two differences between ideal solutions and non-ideal solutions.

2018
1. Calculate the freezing point of a solution containing 60 g of solute in 250 g of water.
(Kf of water = 1.86 K·kg/mol)
2. Give reasons for the following:
a. Measurement of osmotic pressure method is preferred for the determination of molar
masses of macromolecules such as proteins and polymers.
b. Aquatic animals are more comfortable in cold water than in warm water.
c. Elevation of boiling point of 1M KCl solution is nearly double that of 1M sugar
solution.

2019
1. Give reason for the following:
a. Cooking is faster in pressure cooker than in cooking pan.
b. RBC shrink when placed in saline water but swell in distilled water.
2. A solution containing 1.9 g per 100 mL of KCl (M = 74.5 g/mol) is isotonic with a
solution containing 3 g per 100 mL of urea (M = 60). Calculate the degree of dissociation
of KCl solution. Assume both solutions have the same temperature.

2020 Set 1
1. What happens when:
(i) A pressure greater than osmotic pressure is applied on the solution side separated from
solvent by a semipermeable membrane?
(ii) Acetone is added to pure ethanol?
2. State Henry’s law. Calculate the solubility of CO2 in water at 298 K under 760 mm Hg.
(KH for CO2 in water at 298 K is 1.25 × 10^6 mmHg)
 3. The freezing point of a solution containing 5 g of benzoic acid (M = 122 g/mol) in 35 g
of benzene is depressed by 2.94 K. What is the percentage association of benzoic acid if
it forms a dimer in solution?
(Kf for benzene = 4.9 K·kg/mol)

2022 Term I
1. Which of the following conditions is correct for an ideal solution?
Ans. Hmix = 0 and Vmix = 0
2. For determination of molar mass of polymers and proteins, which colligative property is
used?
Ans. Osmotic pressure
3. Pure water boils at 373.15 K and nitric acid boils at 359.15 K. An azeotropic mixture of
H2O boils at 393.55 K. Distilling the azeotropic mixture will cause?
Ans. Both of them to distill over in the same composition as that of the mixture being
distilled.
4. A 5% (by mass) solution of glucose (180 g/mol) is isotonic with 1% solution by mass of
a substance X. The molar mass of X is?
5. When 2.5 g of a non-volatile solute was dissolved in 50 mL of water, it gave boiling
point elevation of 0.52°C. The molar mass of the solute is?
(Kb for water = 0.52 K·m^-1)
Ans. 50 g/mol
6. The solution of a pair of volatile liquids A and B shows negative deviation from Raoult’s
law. This is because –
Ans. The intermolecular force A-A, B-B < A-B
7. Assertion (A): Relative lowering in vapour pressure is a colligative property.
Reason (R): Relative lowering in vapour pressure depends upon mole fraction of pure
solvent.
8. Which of the following analogies is correct?
Ans. π = CRT: Osmotic pressure :: P > π : Reverse osmosis
 Electrochemistry

1. Conductivity of 0.00241 M acetic acid is 7.896 × 10⁻⁵ S cm⁻¹. Calculate its molar
conductivity. If the limiting molar conductivity of acetic acid is 390.5 S cm² mol⁻¹, what
is its degree of dissociation?
2. Write the Nernst equation for the cell and find the emf of the cell at 298 K: Mg(s) | Mg²⁺
(0.001 M) || Cu²⁺ (0.0001 M) | Cu(s)
Given: E°(Mg²⁺/Mg) = -2.36 V, E°(Cu²⁺/Cu) = +0.34 V
3. Represent the cell in which the following reaction takes place: Mg(s) + 2Ag⁺ (0.0001 M)
→ Mg²⁺ (0.130 M) + 2Ag(s). Calculate E_cell if E°_cell = 3.17 V. Calculate Gibbs free
energy change (ΔG) and equilibrium constant (K).
4. Can a nickel spatula be used to stir a solution of copper sulfate? Justify your answer.
(E°Ni²⁺/Ni = -0.25 V, E°Cu²⁺/Cu = 0.34 V)
5. The conductivity of 0.20 M KCl solution at 298 K is 0.0248 S cm⁻¹. Calculate its molar
conductivity.
6. How much charge is required for the following reduction? Al³⁺ → Al (s)
7. Write the Nernst equation for the following cell: Ni(s) + 2Ag⁺ (0.01 M) → Ni²⁺ (0.001
M) + 2Ag(s)
8. Given the standard electrode potentials of different metal ions: K⁺/K = -2.93 V, Ag⁺/Ag =
0.80 V, Hg²⁺/Hg = 0.79 V, Mg²⁺/Mg = -2.37 V, Cr³⁺/Cr = -0.74 V. Arrange these metals
in increasing order of reducing power.
9. Why does conductivity of a solution decrease with dilution?
10. The EMF of a cell corresponding to the reaction (E° Zn²⁺/Zn = -0.76 V): Zn(s) + 2H⁺(aq)
→ Zn²⁺ (0.1 M) + H₂(g, 1 atm) is 0.28 V at 25°C. Write the half-cell reaction and
calculate the pH of the solution at the hydrogen electrode.
11. EMF = 0.2 V at 298 K for the cell: Cd(s) | Cd²⁺ (?) || Ni²⁺ (2.0 M) | Ni(s). Given:
E°Cd²⁺/Cd = -0.40 V, E°Ni²⁺/Ni = -0.25 V