plumiAcids, alkalis and pH: Edexcel GCSE Combined Science questions
Every Edexcel GCSE Combined Science exam question on Acids, alkalis and pH (specification points 3.1–3.8), 2018–2025, with its mark scheme and examiner’s report.
Paper
All papers
Exam
All years
Calculations
Q6(a)
The whole paper ↗Q6(c)
The whole paper ↗Q1(b)(i)
The whole paper ↗Q6(a)(ii)
The whole paper ↗Q5(b)(i)
The whole paper ↗Q1(d)(i)
The whole paper ↗Q1(d)(iii)
The whole paper ↗Q2(c)(i)
The whole paper ↗Q2(c)(ii)
The whole paper ↗Q5(d)(i)
The whole paper ↗Q5(d)(iii)
The whole paper ↗Q5(e)
The whole paper ↗Q1(b)(ii)
The whole paper ↗Q1(b)(iii)
The whole paper ↗Q6(a)(iii)
The whole paper ↗Q5(b)(ii)
The whole paper ↗Q5(b)(iii)
The whole paper ↗Q3(c)
The whole paper ↗Q1(c)(ii)
The whole paper ↗Q4(a)(ii)
The whole paper ↗
All 36 questions on Acids, alkalis and pH, as a list
- June 2025, Chemistry Paper 1 Higher, Q6(a) (2 marks): Ammonia is a gas. Suggest why the litmus paper used to test for ammonia gas has to be damp. (2)
- June 2025, Chemistry Paper 2 Higher, Q6(c) (2 marks): Iodine reacts with hydrogen to form hydrogen iodide, HI. Explain whether or not a solution of hydrogen iodide in water conducts electricity. (2)
- June 2024, Chemistry Paper 1 Higher, Q1(b)(i) (1 mark): Name a piece of equipment that could be used to measure the pH of a substance more accurately than universal indicator paper. (1)
- June 2024, Chemistry Paper 1 Higher, Q6(a)(ii) (4 marks): The dilute hydrochloric acid used in this reaction is a strong acid. Explain the meaning of the terms dilute and strong acid. (4) dilute strong acid
- June 2024, Chemistry Paper 1 Foundation, Q5(b)(i) (1 mark): Name a piece of equipment that could be used to measure the pH of a substance more accurately than universal indicator paper. (1)
- June 2023, Chemistry Paper 1 Higher, Q1(d)(i) (1 mark): Using Figure 1, give the pH of the acid at the start of the experiment. (1) pH =
- June 2023, Chemistry Paper 1 Higher, Q1(d)(iii) (3 marks): Explain why the pH starts at a low value and ends at a higher value. (3)
- June 2023, Chemistry Paper 1 Higher, Q2(c)(i) (1 mark): State how many times greater the concentration of hydrogen ions is in the acid of pH 1 than in the acid of pH 2. (1)
- June 2023, Chemistry Paper 1 Higher, Q2(c)(ii) (1 mark): With the acid of pH 2, the mass of hydrogen gas produced when the reaction is complete is 0.005 g. Predict the mass of hydrogen gas produced in the reaction wit
- June 2023, Chemistry Paper 1 Foundation, Q5(d)(i) (1 mark): Using Figure 7, give the pH of the acid at the start of the experiment. (1) pH =
- June 2023, Chemistry Paper 1 Foundation, Q5(d)(iii) (3 marks): Explain why the pH starts at a low value and ends at a higher value. (3)
- June 2023, Chemistry Paper 1 Foundation, Q5(e) (1 mark): State what should be used to measure the pH of the mixture in this experiment. (1)
- June 2022, Chemistry Paper 1 Higher, Q1(b)(ii) (2 marks): Describe how the pH of the mixture is determined when a drop of it is placed on the universal indicator paper. (2)
- June 2022, Chemistry Paper 1 Higher, Q1(b)(iii) (2 marks): In the method, universal indicator paper is used to determine the pH. Explain why litmus paper would not be a suitable indicator to use in this experiment. (2)
- June 2022, Chemistry Paper 1 Higher, Q6(a)(iii) (2 marks): The reactions between metals and dilute ethanoic acid are slower than reactions between metals and dilute hydrochloric acid. This is because ethanoic acid is a
- June 2022, Chemistry Paper 1 Foundation, Q5(b)(ii) (2 marks): Describe how the pH of the mixture is determined when a drop of it is placed on the universal indicator paper. (2)
- June 2022, Chemistry Paper 1 Foundation, Q5(b)(iii) (2 marks): In the method, universal indicator paper is used to determine the pH. Explain why litmus paper would not be a suitable indicator to use in this experiment. (2)
- June 2022, Chemistry Paper 2 Foundation, Q3(c) (3 marks): Hydrogen chloride gas and sulfur dioxide gas are dissolved in separate test tubes of water. Blue litmus paper is dipped into each test tube. State and explain t
- November 2021, Chemistry Paper 1 Higher, Q1(c)(ii) (1 mark): Hydrogen chloride solution is acidic. The formulae of four ions are shown in Figure 2. H+ H– Cl+ Cl– Figure 2 Give the formula of the ion in Figure 2 that cause
- November 2021, Chemistry Paper 1 Higher, Q4(a)(ii) (1 mark): During the reaction, the pH of the mixture changed from 2 to 6. By what factor has the concentration of the hydrogen ions in the mixture changed? (1) A × 10 000
- November 2021, Chemistry Paper 1 Foundation, Q1(b)(ii) (1 mark): State the information from Figure 1 that shows that the drinking water is neutral. (1)
- November 2021, Chemistry Paper 1 Foundation, Q4(a)(iii) (1 mark): What is the most likely change in pH during the experiment? (1) A from 1 to 7 B from 1 to 12 C from 7 to 12 D from 12 to 1
- November 2021, Chemistry Paper 1 Foundation, Q4(a)(iv) (2 marks): If some methyl orange indicator is added to the acid in step 2, the mixture changes colour during the experiment. State the colour change. (2) colour at start i
- November 2021, Chemistry Paper 1 Foundation, Q5(c)(ii) (1 mark): Hydrogen chloride solution is acidic. The formulae of four ions are shown in Figure 6. H+ H– Cl+ Cl– Figure 6 Give the formula of the ion in Figure 6 that cause
- November 2020, Chemistry Paper 1 Higher, Q6(a)(i) (2 marks): Explain why dilute hydrochloric acid is described as a strong acid. (2)
- November 2020, Chemistry Paper 1 Higher, Q6(a)(ii) (1 mark): 1 cm3 of hydrochloric acid of pH 2 is made up to a volume of 10 cm3 with distilled water. State the pH of the new solution. (1) pH =
- November 2020, Chemistry Paper 1 Higher, Q6(c)(i) (1 mark): Give the name of an alternative piece of equipment that can be used to measure pH. (1)
- November 2020, Chemistry Paper 1 Foundation, Q1(c)(i) (1 mark): State what could be used to measure the pH of a solution. (1)
- November 2020, Chemistry Paper 1 Foundation, Q1(c)(ii) (1 mark): Sodium chloride solution is neutral. Give the pH of this solution. (1)
- June 2019, Chemistry Paper 1 Higher, Q6(a)(i) (1 mark): State what could be used to measure these pH values of 3.40 and 4.40. (1)
- June 2019, Chemistry Paper 1 Higher, Q6(a)(ii) (1 mark): What is the concentration of hydrogen ions in solution X compared with that in solution Y? (1) A ten times lower B lower by a factor of 3.30/4.40 C higher by a
- June 2019, Chemistry Paper 1 Higher, Q6(b)(ii) (1 mark): During the experiment the pH changes from 2 to 10. If phenolphthalein indicator is added at the beginning of the experiment, a colour change occurs as the base
- June 2019, Chemistry Paper 1 Higher, Q6(b)(iii) (2 marks): Explain, in terms of the particles present, why the pH increases during the experiment. (2)
- June 2018, Chemistry Paper 1 Higher, Q6(d) (1 mark): The hydrogen ion concentration in a solution is decreased by a factor of 10. State how the pH of this solution changes. (1)
- June 2018, Chemistry Paper 2 Higher, Q2(d) (1 mark): When the gas hydrogen chloride, HCl, is dissolved in water, a solution forms. Blue litmus paper dipped in this solution turns red. State why the litmus paper tu
- June 2018, Chemistry Paper 2 Foundation, Q5(d) (1 mark): When the gas hydrogen chloride, HCl, is dissolved in water, a solution forms. Blue litmus paper dipped in this solution turns red. State why the litmus paper tu
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