FSc Part 1 Chemistry chapter 9: Solutions MCQs with answers

By Team Megalecture · Updated 4 Nov 2026

29 exam-style questions on Solutions, each with the answer and a short explanation. Ten of them are below to try. The chapter test draws ten fresh questions each time and is marked the moment you finish, with your score by topic.

29 questions · 3 topics · 10 per test

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What chapter 9 covers

Ten Solutions questions with answers

Try each one, then open the answer. These ten stay the same; the test draws new ones every time.

1. 1.8 g of a non-electrolyte in 100 g of water lowers the freezing point by 0.186 K. Kf = 1.86 K kg mol−1. What is the molar mass of the solute?

  1. A
    18 g mol−1
  2. B
    360 g mol−1
  3. C
    180 g mol−1
  4. D
    1.8 g mol−1
Show answer

Answer: C. M = (Kf × 1000 × w2) ÷ (ΔTf × w1) = (1.86 × 1000 × 1.8) ÷ (0.186 × 100) = 3348 ÷ 18.6 = 180 g mol−1.

2. Acetone and chloroform show negative deviation from Raoult's law. Why?

  1. A
    hydrogen bonds form between chloroform and acetone molecules, so A−B attractions are stronger
  2. B
    the molecules of the two liquids repel each other
  3. C
    the two liquids react to form a new compound
  4. D
    both liquids are non-polar
Show answer

Answer: A. The H of CHCl3 hydrogen bonds to the O of acetone. Stronger A−B attractions lower the vapour pressure and heat is released on mixing.

3. 10 g of sodium chloride is dissolved in 90 g of water. What is the percentage by mass (w/w) of NaCl?

  1. A
    11.1%
  2. B
    9.0%
  3. C
    90%
  4. D
    10%
Show answer

Answer: D. % w/w = mass of solute ÷ mass of solution × 100 = 10 ÷ (10 + 90) × 100 = 10%. Dividing by the mass of water only gives 11.1%.

4. Which 0.1 mol kg−1 aqueous solution has the lowest freezing point?

  1. A
    glucose
  2. B
    urea
  3. C
    sodium chloride
  4. D
    calcium chloride
Show answer

Answer: D. CaCl2 gives three ions (Ca2+ + 2Cl−) per formula unit, the most particles, so the largest freezing point depression. NaCl gives two; glucose and urea give one.

5. Which pair of liquids forms a nearly ideal solution?

  1. A
    benzene and toluene
  2. B
    ethanol and water
  3. C
    acetone and chloroform
  4. D
    nitric acid and water
Show answer

Answer: A. Benzene and toluene are very similar, so A−B attractions equal A−A and B−B attractions; ΔHmix = 0 and Raoult's law is obeyed. The others deviate.

6. Colligative properties of a dilute solution depend on

  1. A
    the chemical nature of the solute
  2. B
    the number of solute particles in a given amount of solvent
  3. C
    the colour of the solute
  4. D
    the molar mass of the solvent only
Show answer

Answer: B. Vapour pressure lowering, boiling point elevation, freezing point depression and osmotic pressure all depend on how many solute particles are present, not what they are.

7. A solution shows positive deviation from Raoult's law. Which statement is correct?

  1. A
    A−B attractions are stronger than A−A and B−B attractions
  2. B
    the vapour pressure is lower than predicted by Raoult's law
  3. C
    A−B attractions are weaker than A−A and B−B attractions, so the vapour pressure is higher than predicted
  4. D
    heat is given out on mixing
Show answer

Answer: C. Weaker attractions in the mixture let molecules escape more easily, so the vapour pressure is higher than Raoult's law predicts and mixing is endothermic.

8. 4.0 g of NaOH is dissolved in water and the solution is made up to 250 cm3. What is its molarity?

  1. A
    0.10 mol dm−3
  2. B
    0.016 mol dm−3
  3. C
    1.6 mol dm−3
  4. D
    0.40 mol dm−3
Show answer

Answer: D. 4.0 ÷ 40 = 0.10 mol in 0.250 dm3, so molarity = 0.10 ÷ 0.250 = 0.40 mol dm−3.

9. Kf for water is 1.86 K kg mol−1. What is the freezing point of a 0.10 mol kg−1 aqueous glucose solution?

  1. A
    −0.186 °C
  2. B
    +0.186 °C
  3. C
    −1.86 °C
  4. D
    −0.052 °C
Show answer

Answer: A. ΔTf = Kf × m = 1.86 × 0.10 = 0.186 K below 0 °C. −0.052 °C wrongly uses Kb.

10. Blue copper(II) sulphate crystals turn white when heated strongly. Why?

  1. A
    the copper ions are reduced to copper
  2. B
    the crystals lose their water of crystallisation
  3. C
    the sulphate ions decompose to SO2
  4. D
    the crystals absorb oxygen
Show answer

Answer: B. CuSO4·5H2O → CuSO4 + 5H2O. The hydrated Cu2+ ions give the blue colour; anhydrous CuSO4 is white.

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Solutions: questions students ask

How many Solutions MCQs are there?

29, each with the answer and a short explanation, across 3 topics: Concentration units, Raoult's law, ideal and non-ideal solutions, Colligative properties, hydration and hydrolysis. Every chapter test draws ten of them, so you can take it many times.

Is the FSc Part 1 Chemistry chapter 9 test free?

Yes. The test, the answers and the explanations are free and need no sign-up. Sign in only if you want your scores kept across devices.

How is the chapter test marked?

The moment you press Finish: your score, the right answer and an explanation for every question, and the ones you got wrong saved in My mistakes to retry.

Can I read the explanations in Urdu?

Yes. In practice mode and on your results you can switch the explanations to Urdu.

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