Acid-Base Chemistry

Chemistry, HSSC-Punjab First Year. This chapter is split into 32 topics and has 738 practice questions. The topics covered are listed below, followed by 10 free sample questions from the chapter.

Topics in this chapter

1. Properties of Acids and Bases and Neutralisation 21 questions
2. Converting Between pH, pOH and Concentrations 28 questions
3. Acid-Base Titration Calculations 28 questions
4. Relative Strengths of Acids (Table 9.3) 20 questions
5. pH, pOH and the pH Scale 23 questions
6. Acid-Base Indicators 22 questions
7. Ionic Product of Water 24 questions
8. Buffer Ratio, pKa and Buffer Design 23 questions
9. Hydrolysis Reactions of Salts 20 questions
10. Common Ion Effect on Solubility 20 questions
11. Salt Hydrolysis and Nature of Salt Solutions 28 questions
12. Calculating Ka from pH or Hydronium Concentration 20 questions
13. pH of Strong Alkali Solutions 27 questions
14. Calculating Solubility from Ksp 23 questions
15. Ionisation Constant Ka and Acid Strength 22 questions
16. Conjugate Acid-Base Pairs 26 questions
17. Effect of Adding Strong Acid or Base to a Buffer 20 questions
18. Predicting Precipitation Using the Ionic Product 20 questions
19. Calculating Ksp from Molar Solubility 23 questions
20. pH of Strong Acid Solutions 29 questions
21. Buffer Solutions and Their Action 22 questions
22. Effect of Temperature on Kw and Neutral pH 20 questions
23. Hydronium Concentration of Weak Acids from Ka 27 questions
24. Solubility Product and Ksp Expressions 27 questions
25. Amphoteric Species and Acid-Conjugate Base Strength 20 questions
26. Common Ion Effect 21 questions
27. Degree of Ionisation of Weak Acids 20 questions
28. Lewis Concept of Acids and Bases 23 questions
29. Calculating the pH of a Buffer (Henderson Equation) 24 questions
30. Titration Curves and Choice of Indicator 21 questions
31. Bronsted-Lowry Concept of Acids and Bases 22 questions
32. Dilution and Mixing of Strong Acids and Alkalis 24 questions

Sample questions: Acid-Base Chemistry

10 sample questions with the correct answer and an explanation. Try to answer each one before reading the explanation.

Q1. Equal volumes of 0.001 mol dm⁻³ Ca²⁺ and 0.001 mol dm⁻³ SO₄²⁻ solutions are mixed. Ksp of CaSO₄ = 2 × 10⁻⁵. After mixing the ionic product is 2.5 × 10⁻⁷. Predict:

• A. no precipitate forms(correct answer)
• B. cannot be predicted without the temperature
• C. precipitate forms
• D. the solution is exactly saturated, with no precipitate

Answer: A.Concentrations after mixing are halved: [Ca²⁺] = 5 × 10⁻⁴, [SO₄²⁻] = 5 × 10⁻⁴; ionic product = 2.5 × 10⁻⁷ < Ksp = 2 × 10⁻⁵, so no precipitation occurs.

Q2. Equal volumes of 2 × 10⁻⁴ mol dm⁻³ Ag⁺ and 2 × 10⁻⁴ mol dm⁻³ Cl⁻ solutions are mixed. Ksp of AgCl = 1.8 × 10⁻¹⁰. After mixing the ionic product is 1 × 10⁻⁸. Predict:

• A. cannot be predicted without the temperature
• B. the solution is exactly saturated, with no precipitate
• C. precipitate forms(correct answer)
• D. no precipitate forms

Answer: C.Concentrations after mixing are halved: [Ag⁺] = 1 × 10⁻⁴, [Cl⁻] = 1 × 10⁻⁴; ionic product = 1 × 10⁻⁸ > Ksp = 1.8 × 10⁻¹⁰, so precipitation occurs.

Q3. Equal volumes of 1 × 10⁻⁶ mol dm⁻³ Ag⁺ and 1 × 10⁻⁶ mol dm⁻³ Cl⁻ solutions are mixed. Ksp of AgCl = 1.8 × 10⁻¹⁰. After mixing the ionic product is 2.5 × 10⁻¹³. Predict:

• A. precipitate forms
• B. the solution is exactly saturated, with no precipitate
• C. no precipitate forms(correct answer)
• D. cannot be predicted without the temperature

Answer: C.Concentrations after mixing are halved: [Ag⁺] = 5 × 10⁻⁷, [Cl⁻] = 5 × 10⁻⁷; ionic product = 2.5 × 10⁻¹³ < Ksp = 1.8 × 10⁻¹⁰, so no precipitation occurs.

Q4. Equal volumes of 1 × 10⁻⁴ mol dm⁻³ Ba²⁺ and 1 × 10⁻⁴ mol dm⁻³ SO₄²⁻ solutions are mixed. Ksp of BaSO₄ = 1.1 × 10⁻¹⁰. After mixing the ionic product is 2.5 × 10⁻⁹. Predict:

• A. the solution is exactly saturated, with no precipitate
• B. cannot be predicted without the temperature
• C. precipitate forms(correct answer)
• D. no precipitate forms

Answer: C.Concentrations after mixing are halved: [Ba²⁺] = 5 × 10⁻⁵, [SO₄²⁻] = 5 × 10⁻⁵; ionic product = 2.5 × 10⁻⁹ > Ksp = 1.1 × 10⁻¹⁰, so precipitation occurs.

Q5. Equal volumes of 0.001 mol dm⁻³ Pb²⁺ and 0.001 mol dm⁻³ SO₄²⁻ solutions are mixed. Ksp of PbSO₄ = 1.6 × 10⁻⁸. After mixing the ionic product is 2.5 × 10⁻⁷. Predict:

• A. cannot be predicted without the temperature
• B. no precipitate forms
• C. the solution is exactly saturated, with no precipitate
• D. precipitate forms(correct answer)

Answer: D.Concentrations after mixing are halved: [Pb²⁺] = 5 × 10⁻⁴, [SO₄²⁻] = 5 × 10⁻⁴; ionic product = 2.5 × 10⁻⁷ > Ksp = 1.6 × 10⁻⁸, so precipitation occurs.

Q6. Equal volumes of 0.001 mol dm⁻³ Ca²⁺ and 0.002 mol dm⁻³ F⁻ solutions are mixed. Ksp of CaF₂ = 3.2 × 10⁻¹¹. After mixing the ionic product is 5 × 10⁻¹⁰. Predict:

• A. cannot be predicted without the temperature
• B. the solution is exactly saturated, with no precipitate
• C. no precipitate forms
• D. precipitate forms(correct answer)

Answer: D.Concentrations after mixing are halved: [Ca²⁺] = 5 × 10⁻⁴, [F⁻] = 0.001; ionic product = 5 × 10⁻¹⁰ > Ksp = 3.2 × 10⁻¹¹, so precipitation occurs.

Q7. Equal volumes of 1 × 10⁻⁷ mol dm⁻³ Ag⁺ and 1 × 10⁻⁷ mol dm⁻³ Br⁻ solutions are mixed. Ksp of AgBr = 5 × 10⁻¹³. After mixing the ionic product is 2.5 × 10⁻¹⁵. Predict:

• A. cannot be predicted without the temperature
• B. the solution is exactly saturated, with no precipitate
• C. precipitate forms
• D. no precipitate forms(correct answer)

Answer: D.Concentrations after mixing are halved: [Ag⁺] = 5 × 10⁻⁸, [Br⁻] = 5 × 10⁻⁸; ionic product = 2.5 × 10⁻¹⁵ < Ksp = 5 × 10⁻¹³, so no precipitation occurs.

Q8. Equal volumes of 0.01 mol dm⁻³ Mg²⁺ and 0.01 mol dm⁻³ OH⁻ solutions are mixed. Ksp of Mg(OH)₂ = 1.8 × 10⁻¹¹. After mixing the ionic product is 1.25 × 10⁻⁷. Predict:

• A. precipitate forms(correct answer)
• B. cannot be predicted without the temperature
• C. the solution is exactly saturated, with no precipitate
• D. no precipitate forms

Answer: A.Concentrations after mixing are halved: [Mg²⁺] = 0.005, [OH⁻] = 0.005; ionic product = 1.25 × 10⁻⁷ > Ksp = 1.8 × 10⁻¹¹, so precipitation occurs.

Q9. Equal volumes of 1 × 10⁻⁴ mol dm⁻³ Ca²⁺ and 1 × 10⁻⁴ mol dm⁻³ CO₃²⁻ solutions are mixed. Ksp of CaCO₃ = 3.3 × 10⁻⁹. After mixing the ionic product is 2.5 × 10⁻⁹. Predict:

• A. cannot be predicted without the temperature
• B. no precipitate forms(correct answer)
• C. the solution is exactly saturated, with no precipitate
• D. precipitate forms

Answer: B.Concentrations after mixing are halved: [Ca²⁺] = 5 × 10⁻⁵, [CO₃²⁻] = 5 × 10⁻⁵; ionic product = 2.5 × 10⁻⁹ < Ksp = 3.3 × 10⁻⁹, so no precipitation occurs.

Q10. Equal volumes of 1 × 10⁻⁶ mol dm⁻³ Ba²⁺ and 1 × 10⁻⁶ mol dm⁻³ CO₃²⁻ solutions are mixed. Ksp of BaCO₃ = 1.1 × 10⁻¹⁰. After mixing the ionic product is 2.5 × 10⁻¹³. Predict:

• A. the solution is exactly saturated, with no precipitate
• B. no precipitate forms(correct answer)
• C. precipitate forms
• D. cannot be predicted without the temperature

Answer: B.Concentrations after mixing are halved: [Ba²⁺] = 5 × 10⁻⁷, [CO₃²⁻] = 5 × 10⁻⁷; ionic product = 2.5 × 10⁻¹³ < Ksp = 1.1 × 10⁻¹⁰, so no precipitation occurs.