Chemistry 5070 · O Level
The characteristic properties of acids and bases
89 practice questions on The characteristic properties of acids and bases, with worked solutions and instant marking.
When powdered calcium carbonate is added to dilute hydrochloric acid, calcium chloride, water and carbon dioxide are formed. Which ionic equation, with state symbols included, correctly represents this reaction?
May/June 2015
A colourless solution reacts with magnesium, producing a salt and hydrogen gas. What role is this solution playing?
May/June 2015
A student places a small strip of magnesium ribbon in a crucible and heats it for several minutes. Magnesium oxide is formed.
May/June 2015
Which of these uses of sulfuric acid are correct?
May/June 2016
Which ion is absent in dilute sulfuric acid?
May/June 2016
Four gas jars each hold one of the gases ammonia, chlorine, hydrogen chloride and oxygen. In every jar, a strip of damp blue litmus paper and a strip of damp red litmus paper are added. In which gas jar do both the damp blue litmus paper and the damp red litmus paper change colour?
May/June 2016
An aqueous hydrochloric acid solution has a pH of 2. After $10\,\text{g}$ of sodium chloride has been added, what would the pH of the acid be?
May/June 2016
An aqueous solution of hydrochloric acid has a pH of $2$. After $10\,\text{g}$ of sodium chloride is added, what is the pH of the acid?
May/June 2016
Hydrogen sulfide, H$_2$S, has a straightforward molecular structure and dissolves in water.
May/June 2016
Hydrogen fluoride, HF, consists of simple molecules. It dissolves in water.
May/June 2016
What colour does litmus paper turn when placed in hydrochloric acid?
May/June 2016
A student is provided with a sample of damp soil that is known to be acidic.
May/June 2016
Which statement concerning sulfuric acid is correct? Sulfuric acid is employed
May/June 2017
Which row gives the sequence of increasing pH (from lowest to highest) for strong acids, strong bases, weak acids and weak bases at the same concentration?
May/June 2017
A farmer applied ammonium nitrate, a nitrogenous fertiliser, to a field. On the following day, he applied calcium hydroxide to that same field. As a result, nitrogen was lost from the ammonium nitrate. Which chemical reaction took place?
May/June 2017
Which statement concerning weak acids is correct?
May/June 2017
Which gas, when dissolved in water, produces a solution with a pH above 7?
May/June 2017
A solution of W shows the following properties: • If it is added to solid ammonium chloride in excess, a gas is produced that changes damp red litmus paper to blue. • If it is added in excess to a solution of pH 3, the final solution has a pH of 13. What is W?
May/June 2018
Several properties of compound J are shown below. - It reacts with potassium carbonate to give carbon dioxide. - It reacts with ethanol to form a sweet-smelling liquid. - It reacts with sodium hydroxide to form a salt. What could be a possible identity of J?
May/June 2018
Which two gases in the pair are both not acidic?
May/June 2018
The diagram shows the structure of methanesulfonic acid.
May/June 2018
The structure of sulfamic acid is displayed.
May/June 2018
Why is ethanoic acid referred to as a weak acid?
May/June 2019
Which of these uses of sulfuric acid are correct? 1. used as a bleach in the production of wood pulp for paper 2. used as a preservative for tinned foods 3. used as a raw material for making detergents 4. used for use as a fertiliser
May/June 2019
Powdered calcium carbonate reacts with dilute hydrochloric acid to form calcium chloride, water and carbon dioxide. What is the correct ionic equation, with state symbols, for this reaction?
May/June 2019
Why is ethanoic acid classed as a weak acid?
May/June 2019
Propanoic acid is a weak acid, while calcium hydroxide and calcium oxide are bases.
May/June 2019
Which row gives the pH values for $0.1\,\text{mol dm}^{-3}$ solutions of ammonia, hydrochloric acid, sodium chloride and sodium hydroxide?
May/June 2021
The water in a lake is acidic, and the fish are dying. The lake water must be neutralised. Which compound can be added in excess to neutralise the water in the lake?
May/June 2021
Which row gives the pH values for $0.1\,\text{mol dm}^{-3}$ solutions of ammonia, hydrochloric acid, sodium chloride and sodium hydroxide?
May/June 2021
Aqueous ammonia reacts with a compound to produce the salt ammonium phosphate. What type of reaction does ammonia undergo in order to produce ammonium phosphate?
May/June 2021
Aqueous calcium hydroxide is an alkali. It is neutralised by dilute nitric acid, forming calcium nitrate and water. State the ionic equation for this reaction?
May/June 2022
Which of the following statements about acids and bases is correct?
May/June 2022
When ammonia gas dissolves in water, a reversible reaction occurs. $\text{NH}_3(\text{g}) + \text{H}_2\text{O}(\text{l}) \rightleftharpoons \text{NH}_4^+(\text{aq}) + \text{OH}^-(\text{aq})$ Which statements are correct?
May/June 2022
A separate reaction is carried out for each of three dilute acid solutions, all having a concentration of $0.01\,\text{mol dm}^{-3}$, with excess calcium carbonate, and the reaction is allowed to continue until no more reaction occurs. The same volume of acid is taken in every case. The carbon dioxide given off is collected, and its volume is recorded. Every measurement is made at room temperature and pressure. The results are: Acid 1: $\text{pH} = 2.0$, volume of carbon dioxide produced $= 20\,\text{cm}^3$ Acid 2: $\text{pH} = 1.7$, volume of carbon dioxide produced $= 40\,\text{cm}^3$ Acid 3: $\text{pH} = 3.4$, volume of carbon dioxide produced $= 20\,\text{cm}^3$ What are the possible identities of the acids?
May/June 2022
Which row correctly indicates the possible uses of sulfur dioxide and sulfuric acid?
May/June 2022
The diagram depicts several reactions of butanoic acid. It shows a central butanoic acid structure, reaction with magnesium giving gas A and salt B, reaction with magnesium carbonate giving salt B, gas C and liquid D, and heating with ethanol giving liquid D and organic liquid E.
May/June 2022
Universal indicator is made up of several dyes. The reversible reaction for one dye, $\text{IndOH}$, is shown. $\text{IndOH}(aq) + \text{H}^+(aq) \rightleftharpoons \text{Ind}^+(aq) + \text{H}_2\text{O}(l)$ A few drops of universal indicator solution are placed into $50\,\text{cm}^3$ of water. Then a few drops of dilute hydrochloric acid are added to this mixture. Which row shows what occurs when the acid is added?
May/June 2023
Samples of $\text{HCl}(aq)$ and $\text{HNO}_3(aq)$ are examined with universal indicator paper. The $\text{HCl}(aq)$ sample shows a pH of $4$, while the $\text{HNO}_3(aq)$ sample shows a pH of $2$. Which statement is correct?
May/June 2023
Which two substances combine to produce only a salt and water?
May/June 2023
An organic compound, $P$, is in aqueous solution. The solution has a concentration of $0.1\,\text{mol dm}^{-3}$ and a pH of $3$. A solid is then added to the solution and fizzing is observed. Which equation could represent this reaction?
May/June 2023
At room temperature, compound X is a gas. When X dissolves in water, the resulting solution has a pH of 4. Which statement about compound X is correct?
May/June 2023
Which of the following statements about hydrochloric acid is correct?
May/June 2023
Which two equations account for the fact that adding calcium hydroxide to soil lowers its acidity but also lowers fertiliser efficiency?
May/June 2023
What chemical equation represents the reaction of sodium carbonate with dilute nitric acid?
May/June 2023
Which row gives both the pH and the ion present at the highest concentration in an aqueous alkali?
May/June 2024
A lake contains acidic water, and the fish are dying. The water in the lake must be neutralised so that its pH is near $7$. Which compound is added in excess to neutralise the lake water?
May/June 2024
When one mole of compound $X$ is dissolved in water, it produces two moles of ions. $X$ reacts with ammonium carbonate to produce an acidic gas. What is compound $X$?
May/June 2024
Which of the following statements about weak acids is correct?
May/June 2024
The pH of a dilute sample of ethanoic acid is measured. The equation showing the partial dissociation of ethanoic acid is given below. $\text{CH}_3\text{COOH}(aq) \rightleftharpoons \text{CH}_3\text{COO}^-(aq) + \text{H}^+(aq)$ Aqueous sodium ethanoate, $\text{CH}_3\text{COONa}$, is then added to the dilute ethanoic acid, and the pH is measured once more. What is the starting pH of the dilute ethanoic acid, and what happens to it after aqueous sodium ethanoate has been added?
May/June 2025
Which row shows the equations for the dissociation of methanoic acid and nitric acid?
May/June 2025
Which two substances react together to produce only a salt and water?
Oct/Nov 2015
Which reaction is not a neutralisation reaction?
Oct/Nov 2015
Which reaction is not a neutralisation reaction?
Oct/Nov 2015
Which two substances combine to produce only a salt and water?
Oct/Nov 2015
Two experiments were conducted. In experiment 1, ammonium carbonate reacted with dilute hydrochloric acid. In experiment 2, ammonium carbonate was heated with aqueous sodium hydroxide. For each experiment, the gas given off was tested using damp blue litmus paper and damp red litmus paper. Which row correctly indicates the colour of both pieces of litmus paper at the end of each experiment?
Oct/Nov 2016
Which row gives the pH values for $0.1\,\text{mol dm}^{-3}$ solutions of ammonia, hydrochloric acid, sodium chloride and sodium hydroxide?
Oct/Nov 2016
How many moles of ethanoic acid, $\text{CH}_3\text{CO}_2\text{H}$, are needed to react with one mole of magnesium?
Oct/Nov 2016
When $0.002$ moles of a metal $M$ were reacted with an excess of dilute hydrochloric acid, $48\,\text{cm}^3$ of hydrogen was produced at r.t.p. Which equation is correct for this reaction?
Oct/Nov 2016
Sulfuric acid counts as a strong acid.
Oct/Nov 2016
Three possible applications of sulfuric acid are given.
Oct/Nov 2017
Which compound gives an aqueous solution with a pH below $7$?
Oct/Nov 2017
A domestic cleaning compound is applied to take off calcium carbonate from bathroom surfaces. The compound reacts with the calcium carbonate to produce a soluble salt, carbon dioxide and water. What is the pH of this cleaning compound?
Oct/Nov 2017
Separate samples of copper, copper(II) oxide and copper(II) carbonate are each treated with dilute hydrochloric acid. Which row correctly indicates whether copper(II) chloride is formed?
Oct/Nov 2017
Which ions are present when hydrochloric acid has just neutralised aqueous sodium hydroxide?
Oct/Nov 2017
Which compound gives an aqueous solution with a pH below 7?
Oct/Nov 2017
Three different combinations of a solution and a solid are prepared, as shown in the table. The mixtures are heated. In which mixtures is gas produced?
Oct/Nov 2018
What is one application of sulfuric acid?
Oct/Nov 2018
Sodium hydroxide is introduced into a solution in order to change its pH. A neutral solution is produced. Which statement is correct?
Oct/Nov 2019
Sodium chloride is dissolved in distilled water. Universal indicator is then added to the solution. What colour does the universal indicator show?
Oct/Nov 2019
Which statement concerning ammonia is correct?
Oct/Nov 2019
Solution T shows the following behaviour. 1 It reacts with magnesium to produce a gas. 2 It reacts with calcium carbonate to produce a gas. Which statement about solution T is correct?
Oct/Nov 2019
Which of the following statements about ammonia is correct?
Oct/Nov 2019
Ethanoic acid, $\text{CH}_3\text{COOH}$, is classified as a weak acid.
Oct/Nov 2019
There are two solutions prepared. Solution P is $0.050\,\text{mol dm}^{-3}$ hydrochloric acid. Solution Q is $0.100\,\text{mol dm}^{-3}$ butanoic acid. A $2\,\text{cm}$ strip of magnesium ribbon is placed into $100\,\text{cm}^3$ of each solution. Effervescence is seen in both solutions, but it is quicker in solution P than it is in solution Q. Which statement best explains this observation?
Oct/Nov 2021
In a neutralisation reaction, what particle change takes place?
Oct/Nov 2021
Which of the following statements about acids and bases is correct?
Oct/Nov 2021
Which of the following statements about sulfuric acid is correct?
Oct/Nov 2022
Which equation correctly represents the reaction of carbon dioxide with magnesium hydroxide?
Oct/Nov 2022
The table gives the pH values for several substances that humans can eat or drink. Substances and pH values: $P: 6.6$, $Q: 3.1$, $R: 10.4$, $S: 7.8$ Which statement about these substances is true?
Oct/Nov 2022
Solution X is introduced to a solid salt, so that gas Y is given off. Gas Y dissolves in water, forming a solution with a pH below $7$. What could X and Y be?
Oct/Nov 2022
Limewater consists of calcium hydroxide dissolved in water. Which statement concerning limewater is correct?
Oct/Nov 2023
A student carries out two experiments. In experiment 1, ammonium carbonate is allowed to react with dilute hydrochloric acid. In experiment 2, ammonium carbonate is heated together with aqueous sodium hydroxide. For each experiment, the gas produced is examined using damp blue litmus paper and damp red litmus paper. Which row correctly indicates the colour of both pieces of litmus paper at the end of each experiment?
Oct/Nov 2023
A student carries out a titration using $20.0\,\text{cm}^3$ of $0.0250\,\text{mol dm}^{-3}$ aqueous sodium carbonate and dilute hydrochloric acid. Exactly $15.5\,\text{cm}^3$ of the dilute hydrochloric acid is required to react completely with the aqueous sodium carbonate. Calculate the concentration, in $\text{mol dm}^{-3}$, of the dilute hydrochloric acid.
Oct/Nov 2023
Hydrochloric acid, $\text{HCl}$, is neutralised as it is added to aqueous potassium hydroxide, $\text{KOH}$. $\text{KOH} + \text{HCl} \rightarrow \text{KCl} + \text{H}_2\text{O}$ The reaction gives out heat. $\textbf{P}$ is aqueous potassium hydroxide. $\textbf{Q}$ is $2.24\ \text{mol}/\text{dm}^3$ hydrochloric acid. A student finds the concentration of potassium hydroxide in $\textbf{P}$. The student carries out six experiments. The student: Step 1. uses a volumetric pipette to place $25.0\ \text{cm}^3$ of $\textbf{P}$ into a plastic cup Step 2. uses a measuring cylinder to add $20\ \text{cm}^3$ of distilled water to the plastic cup Step 3. stirs the mixture in the cup with a thermometer and notes its temperature to the nearest $0.5\ ^\circ\text{C}$ Step 4. uses a burette to add $5.0\ \text{cm}^3$ of $\textbf{Q}$ to the plastic cup and stirs Step 5. records the greatest temperature reached Step 6. empties the plastic cup and washes it out with water Step 7. repeats steps $1$-$6$ using five other volumes of distilled water and $\textbf{Q}$ so that the total volume in the cup is always $50\ \text{cm}^3$. The student’s results are given in Table 2.1.
Oct/Nov 2023
Which solid reacts with dilute hydrochloric acid to give off a gas?
Oct/Nov 2024
Which aqueous solution of concentration $1\,\text{mol dm}^{-3}$ has the greatest pH?
Oct/Nov 2024
During a neutralisation reaction, what change happens to the particles?
Oct/Nov 2025
Powdered calcium carbonate is reacted with dilute hydrochloric acid to form calcium chloride, water and carbon dioxide. Which ionic equation, with state symbols included, is correct for this reaction?
Oct/Nov 2025