Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
Carboxylic Acids
48 practice questions
Topics covered
Practice questions
31–40 of 48
Question 31
1 mark · Normal
Answer and check →Which statement best describes a weak acid such as ethanoic acid?
- A.It ionises completely in water.
- B.It ionises partially in water.
- C.It does not ionise in water.
- D.It is less dense than water.
Question 32
2 marks · Normal
Answer and see the solution →Give the name and the molecular formula of the carboxylic acid with three carbon atoms.
Question 33
4 marks · Normal
Answer and see the solution →A student adds blue litmus paper to a solution of butanoic acid then tests its pH before and after adding sodium carbonate. Answer the following questions.
(a)[1 mark]State what is observed when the blue litmus paper is placed in butanoic acid.
(b)[1 mark]Give a likely pH value for butanoic acid.
(c)[1 mark]State what you would observe after adding sodium carbonate to the butanoic acid.
(d)[1 mark]Explain why the pH of the solution increases after adding sodium carbonate.
Question 34
3 marks · Normal
Answer and see the solution →A student reacts 4.8 g of magnesium ribbon with excess ethanoic acid. Magnesium reacts with ethanoic acid as shown:
Calculate the maximum volume of hydrogen gas produced at room temperature and pressure (rtp), assuming 1 mole of gas occupies 24 dm³. (Relative atomic mass: Mg = 24)
Question 35
2 marks · Hard
Answer and see the solution →Butanoic acid and hydrochloric acid have the same concentration. Explain why the pH of butanoic acid is higher than that of hydrochloric acid.
Question 36
5 marks · Hard
Answer and see the solution →A solution of ethanoic acid is reacted with calcium carbonate (CaCO₃) powder in a test-tube.
(a)[1 mark]State one observation you would make during the reaction.
(b)[2 marks]Write a balanced symbol equation for the reaction.
(c)[1 mark]Name the salt formed.
(d)[1 mark]Ethanoic acid reacts more slowly than hydrochloric acid of the same concentration. Explain why.
Question 37
2 marks · Hard
Answer and see the solution →Describe two ways you could show that propanoic acid is a weak acid.
Question 38
5 marks · Easy
Answer and see the solution →Methanoic acid is the first member of the carboxylic acid homologous series.
(a)[1 mark]Draw the displayed formula of methanoic acid.
(b)[1 mark]Name the salt formed when methanoic acid reacts with magnesium.
(c)[2 marks]Write a balanced chemical equation for the reaction between methanoic acid and magnesium.
(d)[1 mark]What would you observe during this reaction?
Question 39
5 marks · Easy
Answer and see the solution →Carboxylic acids are weak acids and react with metals to produce salts.
(a)[1 mark]State the name of the unbranched-chain carboxylic acid with four carbon atoms.
(b)[1 mark]Write its molecular formula.
(c)[2 marks]Describe what is meant by a 'weak acid'.
(d)[1 mark]Explain why carboxylic acids react more slowly with magnesium than hydrochloric acid.
Question 40
5 marks · Easy
Answer and see the solution →Vinegar is a dilute solution of ethanoic acid and reacts with sodium carbonate.
(a)[1 mark]State the name and molecular formula of the main acid present in vinegar.
(b)[2 marks]Write a balanced chemical equation for the reaction between ethanoic acid and sodium carbonate.
(c)[2 marks]Calculate the maximum volume of carbon dioxide (in dm³ at room temperature and pressure) produced if 0.1 mol of sodium carbonate reacts completely with excess ethanoic acid.