Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
Acids, Alkalis and Titrations
83 practice questions
Topics covered
Practice questions
1–10 of 12 · Hard
Question 1
2 marks · Hard
Answer and see the solution →State the colours that phenolphthalein and methyl orange turn in a strongly alkaline solution.
Question 2
5 marks · Hard
Answer and see the solution →An unknown solution is tested with universal indicator. The indicator turns blue-green and the estimated pH is 8.
(a)[2 marks]Use the pH scale to classify the solution as strongly acidic, weakly acidic, neutral, weakly alkaline, or strongly alkaline. Give a reason for your answer.
(b)[1 mark]State what the pH value tells you about the concentration of hydrogen ions compared to a solution of pH 7.
(c)[2 marks]Describe how you would use universal indicator to estimate the pH of an aqueous solution. Include what you would observe and what you would compare it to.
Question 3
2 marks · Hard
Answer and see the solution →Explain how adding an acid to an alkaline solution changes its pH. State what happens to the indicator colour if universal indicator is used throughout.
Question 4
2 marks · Hard
Answer and see the solution →State the colours shown by phenolphthalein in (i) a strongly acidic solution, and (ii) a strongly alkaline solution.
Question 5
5 marks · Hard
Answer and see the solution →For each pH value below, state whether the solution is strongly acidic, weakly acidic, neutral, weakly alkaline, or strongly alkaline.
(a)[1 mark]pH = 2
(b)[1 mark]pH = 5
(c)[1 mark]pH = 7
(d)[1 mark]pH = 9
(e)[1 mark]pH = 12
Question 6
2 marks · Hard
Answer and see the solution →Describe how you would use universal indicator paper to measure the pH of a solution as accurately as the method allows.
Question 7
2 marks · Hard
Answer and see the solution →State the name and the full chemical formula of the ion that is present in all acidic solutions and causes acidity.
Question 8
5 marks · Hard
Answer and see the solution →The following table shows two acids and their reactions in water.
Acid Equation in water Acid A Acid B (a)[1 mark]For Acid A, explain what the presence of H^+ ions in solution tells you about the nature of the solution.
(b)[1 mark]For Acid B, how many moles of H^+ ions are formed from 1 mole of HB_2?
(c)[2 marks]Both Acid A and Acid B are added separately to water to make solutions.
Describe in terms of ions what occurs in each solution and which property they share.
(d)[1 mark]Explain, using one example from above, what is meant by the 'replaceable hydrogen' in acids.
Question 9
2 marks · Hard
Answer and see the solution →Name one metal compound (other than ammonia or sodium hydroxide) that makes water alkaline and write a balanced equation to show the formation of hydroxide ions in this solution.
Question 10
2 marks · Hard
Answer and see the solution →State two steps you must carry out before starting to add alkali from a burette in a titration experiment between hydrochloric acid and sodium hydroxide. Do not include steps taken during or after the addition of alkali.