Acids, bases and salts — IGCSE Science - Combined (0653) questions by topic
Word and symbol equations for making salts sit at the centre of this topic, from completing Zn(s) + HCl(aq) reactions to describing how excess base is filtered off before evaporation, alongside practical steps such as using universal indicator to measure pH. Suggest and describe are the commonest command words, both demanding a specific procedure rather than a general statement.
These 22 questions span 2023 to 2025 papers and carry between 1 and 13 marks, so a one-word gap-fill can sit alongside a full method write-up. Submitting each attempt for instant marking is the quickest way to see whether a described method actually names the reagent and step the mark scheme rewards, rather than a vaguer version of it.
What examiners look for
- A common slip is saying the solution is heated so that 'it' evaporates, without specifying that water is the substance evaporating.
- Excess base must be stated explicitly; omitting that magnesium oxide is added in excess costs the mark for ensuring all the acid reacts.
- Reports criticise vague explanations of experimental error such as 'human error', where a specific source of imprecision is required instead.
- Strong answers identify hydrochloric acid as the acid needed to produce a metal chloride, and go on to describe filtering off unreacted solid before evaporating to crystallise.
- Candidates who read the pH colour carefully placed it correctly between two reference colours, such as pH 9 sitting between dark green (pH 8) and blue (pH 10).
May–June 2025, Paper 11
Excess solid zinc carbonate is added to dilute hydrochloric acid in a beaker. When the reaction is complete, the beaker contains a mixture of unreacted solid zinc carbonate in a…
Answer this question and get it marked →May–June 2025, Paper 12
Which row describes an acid? pH reaction with metals reaction with bases --- --- --- --- A 2 forms water forms hydrogen B 3 forms hydrogen forms water C 4 forms hydrogen forms…
Answer this question and get it marked →May–June 2025, Paper 13
Universal indicator is placed into a colourless liquid. The colour change of the universal indicator shows that the pH of the liquid is 6. Which statement about the colourless…
Answer this question and get it marked →Sodium nitrate, NaNO3, is a soluble salt. Which method is used to make pure solid sodium nitrate? A Add aqueous sodium hydroxide to a conical flask, titrate with dilute nitric…
Answer this question and get it marked →May–June 2025, Paper 21
An excess of an insoluble metal carbonate is mixed with an acid. A salt is produced. Which row shows steps to obtain a pure salt from the reaction mixture? step 1 step 2 --- ---…
Answer this question and get it marked →May–June 2025, Paper 22
Which word equation represents the reaction of an acid with a carbonate? A acid + carbonate → salt + carbon dioxide B acid + carbonate → salt + carbon dioxide + water C acid +…
Answer this question and get it marked →May–June 2025, Paper 23
Which formula does not represent an acid? A H₂SO₄ B HCl C HNO₃ D NH₃
Answer this question and get it marked →Barium sulfate is an insoluble salt. It is made when aqueous barium chloride reacts with compound W. Which row identifies compound W and the method used to obtain barium sulfate…
Answer this question and get it marked →May–June 2025, Paper 33
Dilute sulfuric acid is used in an electrolysis experiment. Universal indicator is used to measure the pH of the dilute sulfuric acid. Describe how to use universal indicator to…
Answer this question and get it marked →May–June 2025, Paper 41
This question is about ionic compounds. Dilute nitric acid and solid copper oxide react to form copper nitrate. Copper oxide is an insoluble base and copper nitrate is a soluble…
Answer this question and get it marked →May–June 2024, Paper 42
Solid magnesium and some magnesium compounds react with dilute acids to make salts. Some of the reactants and products of these reactions are shown in Table 8.1. Complete Table…
Answer this question and get it marked →May–June 2024, Paper 43
Zinc and some zinc compounds react with dilute acids to make salts. Complete the word equations for the following reactions. zinc + sulfuric acid → + hydrogen + hydrochloric acid…
Answer this question and get it marked →October–November 2024, Paper 31
A student investigates the rate of reaction between solid magnesium carbonate and dilute hydrochloric acid. Fig. 2.1 shows the apparatus: a conical flask containing lumps of solid…
Answer this question and get it marked →October–November 2024, Paper 32
A student investigates the rate of reaction between pieces of calcium metal and dilute hydrochloric acid. The mass is recorded every 30 s during the reaction. Fig. 2.1 shows the…
Answer this question and get it marked →October–November 2024, Paper 33
A student investigates the rate of reaction between pieces of calcium metal and dilute hydrochloric acid. The mass is recorded every 30 s during the reaction. Fig. 2.1 shows the…
Answer this question and get it marked →October–November 2024, Paper 41
Silver chloride, magnesium chloride and sodium chloride are salts. (a) The equation shows a reaction used to prepare silver chloride, AgCl. AgNO3(aq) + NaCl(aq) → AgCl(......) +…
Answer this question and get it marked →October–November 2024, Paper 42
Carbon dioxide is a gas in air. (a) Dilute hydrochloric acid reacts with calcium carbonate to form carbon dioxide. State the names of the two other products formed when dilute…
Answer this question and get it marked →October–November 2024, Paper 43
(a) Excess solid zinc is added to dilute hydrochloric acid in a conical flask. (a)(i) Complete the equation for the reaction. Zn(s) + ......HCl(aq) → ZnCl2(aq) + ......(g)
Answer this question and get it marked →May–June 2023, Paper 31
Copper(II) sulfate, CuSO4, can be made by reacting copper(II) oxide, CuO, with a dilute acid. Complete the word equation for the formation of copper(II) sulfate from copper(II)…
Answer this question and get it marked →May–June 2023, Paper 33
Magnesium sulfate is produced by reacting excess magnesium oxide with dilute sulfuric acid. Complete the word equation for this reaction. + → magnesium sulfate +
Answer this question and get it marked →October–November 2023, Paper 42
Magnesium chloride is a soluble salt. Magnesium chloride is made in the reaction between solid magnesium oxide and a dilute acid (Fig. 2.1 shows solid magnesium oxide being added…
Answer this question and get it marked →October–November 2023, Paper 63
A student investigates a white solid, H. The student dissolves some solid H in distilled water, adds universal indicator, and compares the colour with a pH colour chart; the…
Answer this question and get it marked →Other IGCSE Science - Combined topics
- Practical skills (96)
- Motion, forces and energy (53)
- Electricity and magnetism (38)
- Waves (32)
- Human nutrition (23)
- Organisms and their environment (21)
- Organic chemistry (21)
- Reproduction (20)
- Thermal physics (20)
- Plant nutrition (19)
- The Periodic Table (18)
- Metals (18)