Barker College Chemistry Department
Past HSC Chemistry Questions
Please click the following link for the past papers of the new syllabus: HOME | Past Hsc Chem3 (andrewchoi2.wixsite.com)
2003 - Q8
A sulfuric acid solution has a concentration of 5 × 10−4 mol L−1 . What is the pH of this solution, assuming the acid is completely ionised?
(A) 3.0
(B) 3.3
(C) 3.6
(D) 4.0
2001 - Q20 (4 marks)
A 0.1 M solution of hydrochloric acid has a pH of 1.0, whereas a 0.1 M solution of citric acid has a pH of 1.6
(a) State ONE way in which pH can be measured. (1 mark)
(b) Explain why the two solutions have different pH values. (3 marks)
2004 - Q7
The figure shows the pH values of some substances.
Based on the pH values shown in the figure, which of the following statements about the concentration of hydrogen ions is correct?
(A) It is twice as great in milk as that in lemon juice.
(B) It is 1 000 000 times greater in soap than in wine.
(C) It is three times greater in wine than in bleach solution.
(D) It is 1 000 times greater in distilled water than in soap
2002 - Q22 (5 marks)
Solutions of hydrochloric acid, acetic acid and sulfuric acid were prepared. Each of the solutions had the same concentration (0.01 M). The pH of the acetic acid solution was 3.4.
(a) Calculate the pH of the hydrochloric acid solution (1 mark)
(b) Compare the pH of the sulfuric acid solution to the pH of the hydrochloric acid solution. Justify your answer. (No calculations are necessary.) (2 marks)
(c) Explain why the acetic acid solution has a higher pH than the hydrochloric acid solution. (2 marks)
2005 - Q8
What would be the pH of a 0.1 mol L−1 solution of sulfuric acid?
(A) Less than 1.0
(B) Exactly 1.0
(C) Between 1.0 and 7.0
(D) Greater than 7.0
2006 - Q8
Acid X is 0.1 mol L–1 hydrochloric acid.
Acid Y is 1.0 mol L–1 acetic acid (ethanoic acid).
How does acid X compare with acid Y?
(A) X is weaker and more dilute than Y.
(B) X is stronger and more dilute than Y.
(C) X is weaker and more concentrated than Y.
(D) X is stronger and more concentrated than Y
2007 - Q8
Acid X and acid Y are both monoprotic weak acids of equal concentration. Acid X is a stronger acid than acid Y.
Which statement about acid X and acid Y is correct?
(A) Acid Y is completely ionised in solution.
(B) The solution of acid X is less ionised than the solution of acid Y.
(C) The solution of acid X has a lower pH than the solution of acid Y.
(D) 1 mole of acid Y requires a greater volume of 1.0 M
NaOH for neutralisation than 1 mole of acid X.
2007 - Q10
A 0.1 mol L–1 HCl solution has a pH of 1.0 .
What volume of water must be added to 90 mL of this solution to obtain a final pH of 2.0?
(A) 10 mL
(B) 180 mL
(C) 810 mL
(D) 900 mL
2008 - Q14
20 mL of 0.08 mol L–1 HCl is mixed with 30 mL of 0.05 mol L–1 NaOH. What is the pH of the resultant solution?
(A) 1.1
(B) 2.7
(C) 4.0
(D) 7.0
2004 - Q24 (5 marks)
The diagram shows three reagent bottles containing acids.
(a) Calculate the pH after 10.0 mL of 0.01 mol L−1 hydrochloric acid solution is diluted by the addition of 90.0 mL of distilled water. (1 mark)
(b) Explain the use of acetic acid and citric acid as food additives. (2 marks)
(c) Explain the difference in pH between the three acids in the diagram. (2 marks)
2006 - Q17 (4 marks)
(a) Calculate the pH of a 0.2 mol L–1 solution of hydrochloric acid. (1 mark)
(b) Calculate the pH after 20 mL of 0.01 mol L–1 sodium hydroxide is added to 50 mL of 0.2 mol L–1 hydrochloric acid. Include a balanced chemical equation in your answer. (3 marks)
2007 - Q21 (5 marks)
(a) State what colour the red cabbage indicator would be in a 0.005 M solution of H2SO4. Show your working. (1 mark)
(b) Using the red cabbage indicator, what colour would the solution be if 10 mL of 0.005 mol L–1 H2SO4 was diluted to 100 mL? (1 mark)
(c) What volume of 0.005 mol L–1 KOH is required to neutralise 15 mL of the diluted solution of H2SO4? (3 marks)
2010 - Q7
Equal volumes of four 0.1 mol L−1 acids were titrated with the same sodium hydroxide solution. Which one requires the greatest volume of base to change the colour of the indicator?
(A) Citric acid
(B) Acetic acid
(C) Sulfuric acid
(D) Hydrochloric acid
2010 - Q21 (3 marks)
A 0.001 mol L−1 solution of hydrochloric acid and a 0.056 mol L−1 solution of ethanoic acid both have a pH of 3.0. Why do both solutions have the same pH?
2012 - Q28 (3 marks)
A solution was made by mixing 75.00 mL of 0.120 mol L−1 hydrochloric acid with 25.00 mL of 0.200 mol L−1 sodium hydroxide.
What is the pH of the solution?
2012 - Q11
The pH of 0.1 mol L–1 solutions of acetic, citric and hydrochloric acids was measured. Which solution has the highest pH?
(A) Citric acid
(B) Acetic acid
(C) Hydrochloric acid
(D) The pH of the three solutions is the same.
2012 - Q18
Which of the following changes take place when 50 mL of water is added to 50 mL of 0.1 mol L–1 acetic acid?
pH Degree of ionisation
(A) Increase Decrease
(B) Decrease Increase
(C) Increase Increase
(D) Decrease Decrease
2015 - Q26 (7 marks)
A sodium hydroxide solution was titrated against citric acid (C6H8O7) which is triprotic.
(a) Draw the structural formula of citric acid (2−hydroxypropane−1,2,3−tricarboxylic acid). (1 mark)
(b) How could a computer‑based technology be used to identify the equivalence point of this titration? (2 marks)
(c) The sodium hydroxide solution was titrated against 25.0 mL samples of 0.100 mol L−1 citric acid. The average volume of sodium hydroxide used was 41.50 mL.
Calculate the concentration of the sodium hydroxide solution. (4 marks)
2012 - Q19
What mass of anhydrous sodium carbonate is required to neutralise 100.0 mL of 0.500 mol L–1 acetic acid?
(A) 2.65 g
(B) 5.30 g
(C) 10.6 g
(D) 53.0 g
2013 - Q8
Which of the following structural formulae shows citric acid, also known as 2-hydroxypropane-1,2,3-tricarboxylic acid?
2013 - Q15
A pH 3.0 solution of HCl(aq) is diluted by adding water to produce a pH 5.0 solution.
Which row in the following table correctly identifies an appropriate volume of the original solution and the volume of water added for this dilution?
Volume of original solution (mL) Volume of water added (mL)
(A) 100 900
(B) 100 1000
(C) 10 990
(D) 1 1000
2014 - Q8
The graph shows the pH of a solution of a weak acid, HA, as a function of temperature.
What happens as the temperature decreases?
(A) HA becomes less ionised and the H+ concentration increases.
(B) HA becomes less ionised and the H+ concentration decreases.
(C) HA becomes more ionised and the H+ concentration increases.
(D) HA becomes more ionised and the H+ concentration decreases.
2014 - Q12
The diagram shows the pH values of some substances.
Based on the information provided, which of the following statements about the relative concentration of hydrogen ions is correct?
(A) It is 2 times higher in bleach than in milk.
(B) It is 10 times lower in stomach acid than in soap.
(C) It is 1000 times lower in distilled water than in wine.
(D) It is 100 times higher in laundry detergent than in baking soda solution.
2014 - Q14
What is the pH of a 0.018 mol L−1 solution of hydrochloric acid?
(A) 0.74
(B) 0.96
(C) 1.04
(D) 1.74
2015 - Q13
Which of the following solutions has the highest pH?
(A) 1.0 mol L−1 acetic acid
(B) 0.10 mol L−1 acetic acid
(C) 1.0 mol L−1 hydrochloric acid
(D) 0.10 mol L−1 hydrochloric acid
2016 - Q6
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Which combination of equimolar solutions would produce the most basic mixture?
(A) Acetic acid and barium hydroxide
(B) Acetic acid and sodium carbonate
(C) Sulfuric acid and barium hydroxide
(D) Sulfuric acid and sodium carbonate
2016 - Q12
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Which of the following could be added to 100 mL of 0.01 mol L–1 hydrochloric acid solution to change its pH to 4?
(A) 900 mL of water
(B) 900 mL of 0.01 mol L–1 hydrochloric acid
(C) 9900 mL of water
(D) 9900 mL of 0.01 mol L–1 hydrochloric acid
2016 - Q18
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40 mL of 0.10 mol L–1 NaOH is mixed with 60 mL of 0.10 mol L–1 HCl.
What is the pH of the resulting solution?
(A) 7.0
(B) 1.7
(C) 1.4
(D) 1.2