Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Theories of acids and bases
19 practice questions
Practice questions
1–8 of 8 · Easy
Question 1
1 mark · Easy
Answer and see the solution →State, according to the Arrhenius theory, what an alkali produces in water.
Question 2
3 marks · Easy
Answer and see the solution →Ammonia reacts with hydrochloric acid to form ammonium chloride. Use the Bronsted-Lowry theory to explain this reaction.
(a)[1 mark]State which reactant acts as the acid.
(b)[1 mark]State which reactant acts as the base.
(c)[1 mark]Explain your answers in terms of proton transfer.
Question 3
2 marks · Easy
Answer and see the solution →For the following reaction, identify the Bronsted-Lowry acid and base on the left-hand side.
(a)[1 mark]Identify the acid.
(b)[1 mark]Identify the base.
Question 4
2 marks · Easy
Answer and see the solution →Describe how the hydroxonium ion, H_3O^+, forms when an acid is added to water, and explain its importance in acid–base reactions.
Question 5
3 marks · Easy
Answer and see the solution →The table shows whether these reactions occur in water according to the Arrhenius and Bronsted-Lowry theories.
Reactions and Theories Reaction Explained by Arrhenius? Explained by Bronsted-Lowry? HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l) Yes Yes NH3(aq) + H2O(l) → NH4+(aq) + OH-(aq) No Yes HCl(g) + NH3(g) → NH4Cl(s) No Yes (a)[1 mark]According to the table, which theory can explain all three reactions?
(b)[1 mark]Which reaction(s) are explained only by the Bronsted-Lowry theory, not the Arrhenius theory?
(c)[1 mark]State one key difference between the two theories based on the reactions above.
Question 6
1 mark · Easy
Answer and see the solution →State what happens to a base in a Bronsted-Lowry acid–base reaction.
Question 7
3 marks · Easy
Answer and see the solution →For each of the following reactions, identify the acid and the base according to the Bronsted-Lowry theory.
(a)[1 mark]Acid: ________ Base: ________
(b)[1 mark]Acid: ________ Base: ________
(c)[1 mark]Acid: ________ Base: ________
Question 8
2 marks · Easy
Answer and see the solution →The reaction below shows how the hydroxonium ion reacts with a base.
a) Identify the base. b) Calculate how many molecules of water are formed when 1 mole of H_3O^+ reacts completely with 1 mole of OH^-.
(a)[1 mark]Name the base in this reaction.
(b)[1 mark]Give the number of water molecules formed (state your answer as a number).