Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Theories of acids and bases
19 practice questions
Practice questions
1–8 of 8 · Normal
Question 1
2 marks · Normal
Answer and see the solution →State two differences between the Arrhenius and Bronsted-Lowry theories of acids and bases.
Question 2
4 marks · Normal
Answer and see the solution →Hydrogen chloride (HCl) and ammonia (NH_3) both undergo acidbase reactions according to the Bronsted-Lowry theory.
(a)[1 mark]Write a balanced equation (with state symbols) for the reaction between aqueous ammonia and hydrochloric acid.
(b)[1 mark]Identify which substance acts as the acid and which acts as the base in this reaction, according to the Bronsted-Lowry theory.
(c)[2 marks]Explain your answer to part (b) in terms of proton transfer.
Question 3
3 marks · Normal
Answer and see the solution →In the reaction: \[ HNO_3(aq) + NH_3(aq) \rightarrow NH_4^+(aq) + NO_3^-(aq) \] use the Bronsted-Lowry definition to identify:
(a)[1 mark]The acid and the base on the left side of the equation. (1 mark)
(b)[1 mark]The conjugate acid and conjugate base formed on the right side. (1 mark)
(c)[1 mark]State which species donates the proton and which accepts it. (1 mark)
Question 4
3 marks · Normal
Answer and see the solution →Explain how the hydroxonium ion (H_3O^+) is formed when an acid dissolves in water, and describe its role in acidbase reactions.
Question 5
4 marks · Normal
Answer and see the solution →The table below shows five example reactions. For each reaction, state which theory (Arrhenius, Bronsted-Lowry, or both) can be used to explain it, and give a reason for your choice.
Acid-base reactions for theory comparison Equation Theory (Arrhenius / Bronsted-Lowry / Both) Reason HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l) HCl(g) + NH3(g) → NH4Cl(s) HNO3(aq) + NH3(aq) → NH4NO3(aq) H2O(l) + NH3(g) → NH4^+(aq) + OH^-(aq) NH4^+(aq) + OH^-(aq) → NH3(aq) + H2O(l) Question 6
1 mark · Normal
Answer and check →According to the Bronsted-Lowry theory, what is a base?
- A.A substance that donates a proton.
- B.A substance that accepts a proton.
- C.A substance that donates electrons.
- D.A substance that accepts electrons.
Question 7
2 marks · Normal
Answer and see the solution →Use the Bronsted-Lowry definition to identify the acid and base in the following reaction: \[ H_2SO_4(aq) + CuO(s) \rightarrow CuSO_4(aq) + H_2O(l) \] State which is the acid and which is the base.
Question 8
4 marks · Normal
Answer and see the solution →The hydroxonium ion, H_3O^+, plays a key role in acidbase reactions.
(a)[2 marks]Draw a dot-and-cross diagram to show the bonding in a hydroxonium ion, H_3O^+.
(b)[2 marks]Explain, in terms of proton transfer, how H_3O^+ is formed from HCl and H_2O.