Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
Acids, Alkalis and Titrations
83 practice questions
Topics covered
Practice questions
11–20 of 36 · Normal
Question 11
3 marks · Normal
Answer and see the solution →A solution has a pH of 2.5. State whether this solution is strongly acidic, weakly acidic, neutral, weakly alkaline, or strongly alkaline. Explain your answer using the pH range classifications.
Question 12
3 marks · Normal
Answer and see the solution →Explain why universal indicator is preferred over litmus paper when measuring the pH of a solution.
Question 13
4 marks · Normal
Answer and see the solution →A student tests four solutions using different indicators. Their observations are shown below.
Observations with indicators Solution Litmus Methyl Orange Universal Indicator A blue yellow blue B red red red C purple orange green D blue yellow green Complete the table below by identifying the likely pH or classification (acidic, neutral, or alkaline) for each solution.
Solution pH/classification A B C D Question 14
1 mark · Normal
Answer and check →Which pH value below would be classified as weakly alkaline?
- A.pH 12
- B.pH 9
- C.pH 7
- D.pH 3
Question 15
2 marks · Normal
Answer and see the solution →You are given a colourless solution that could be either hydrochloric acid or sodium hydroxide solution. Describe how you would use universal indicator to help identify which solution is which.
Question 16
4 marks · Normal
Answer and see the solution →(a)[2 marks]Complete the table to show the colour each indicator would turn in a neutral solution (pH 7).
Indicator Colour in Neutral Solution Litmus Methyl orange Phenolphthalein Universal indicator (b)[2 marks]Suggest why universal indicator is more useful than phenolphthalein for measuring the pH of a weakly acidic solution.
Question 17
2 marks · Normal
Answer and see the solution →State the name and the formula of the ion responsible for acidity in aqueous solutions.
(a)[1 mark]Name of the ion:
(b)[1 mark]Formula of the ion:
Question 18
4 marks · Normal
Answer and see the solution →Potassium carbonate and ammonia both form alkaline solutions in water.
(a)[2 marks]Write a balanced chemical equation to show how ammonia forms an alkaline solution when dissolved in water.
(b)[2 marks]State the name and formula of the ion responsible for alkalinity in these solutions.
Question 19
3 marks · Normal
Answer and see the solution →Explain why a solution of sodium carbonate in water is alkaline, even though sodium carbonate does not contain hydroxide ions in its original formula.
Question 20
4 marks · Normal
Answer and see the solution →The following table shows the concentration of hydrogen ions in different solutions.
Solution [H^+] (mol/dm³) A 1.0 × 10^{-2} B 1.0 × 10^{-6} C 1.0 × 10^{-4} D 1.0 × 10^{-8} (a)[2 marks]Which solution is the most acidic? Explain your answer.
(b)[1 mark]Which solution is likely to have a pH above 7? Give the letter.
(c)[1 mark]State the relationship between hydrogen ion concentration and acidity.