Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
Carboxylic Acids
48 practice questions
Topics covered
Practice questions
11–19 of 19 · Easy
Question 11
2 marks · Easy
Answer and see the solution →A student reacts 0.81 g of magnesium with excess butanoic acid. Calculate the maximum volume of hydrogen gas produced at room temperature and pressure. (1 mol of any gas occupies 24 dm³ at r.t.p.; Mg = 24.3 g/mol)
Question 12
2 marks · Easy
Answer and see the solution →Explain why carboxylic acids such as ethanoic acid have a higher pH than hydrochloric acid of the same concentration.
Question 13
1 mark · Easy
Answer and see the solution →State the products formed when dilute butanoic acid reacts with magnesium metal.
Question 14
3 marks · Easy
Answer and see the solution →Ethanoic acid is a weak acid. A student places blue litmus paper into a solution of ethanoic acid and measures the pH.
(a)[1 mark]State the expected colour change of the litmus paper.
(b)[1 mark]Ethanoic acid reacts with sodium carbonate solution. Write the chemical name of the gas produced.
(c)[1 mark]Describe what is meant by a 'weak acid' in terms of ionisation in water.
Question 15
2 marks · Easy
Answer and see the solution →A student reacts 1.2 g of magnesium with excess propanoic acid.
Calculate the maximum volume of hydrogen gas produced at room temperature and pressure. (Molar mass of Mg = 24 g/mol, 1 mol gas = 24 dm³ at r.t.p.)
Question 16
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 17
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 18
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.
Question 19
5 marks · Easy
Answer and see the solution →Propanoic acid is a member of the carboxylic acid family.
(a)[1 mark]Draw the displayed formula of propanoic acid.
(b)[2 marks]State why propanoic acid is described as a weak acid.
(c)[2 marks]A piece of magnesium ribbon is added to propanoic acid. What do you expect to observe? Explain your answer.