The characteristic properties of acids and bases

Four separate solutions, W, X, Y and Z, are checked with Universal Indicator. Solution W produces green, X produces red, Y produces purple, and Z produces orange. Which solutions are acidic?

Feb/March 2016

Methyl orange becomes red in the solution produced when substance R reacts with water. Which substance is R?

Feb/March 2016

What is the reason for a farmer adding lime (calcium oxide) to soil?

Feb/March 2016

Which structure is the one for a compound that, when dissolved in water, forms an acidic solution?

Feb/March 2016

Concentrated hydrochloric acid is classed as a strong acid. What do the terms "strong" and "acid" mean?

Feb/March 2016

Which property is shown by concentrated sulfuric acid but not by dilute sulfuric acid?

Feb/March 2016

For what reason would a farmer add lime (calcium oxide) to the soil?

Feb/March 2016

Which reaction counts as a neutralisation reaction?

Feb/March 2017

Elements W and X are metals. Elements Y and Z are non-metals. When the oxides of W, X, Y and Z are each added to water, they all produce solutions. Which statement is correct?

Feb/March 2017

Ammonia is made when a mixture of ammonium chloride and substance X is heated. Identify substance X.

Feb/March 2017

In the apparatus illustrated, a gas is given off at point Q. Which gas makes the damp Universal Indicator paper change colour most rapidly?

Feb/March 2017

What property is displayed by sodium hydroxide, an alkali?

Feb/March 2018

The list shows four experiments involving calcium carbonate. 1 acid added 2 alkali added 3 heated strongly 4 water added Which experiments released carbon dioxide?

Feb/March 2018

The diagram gives the pH readings for the soil in two sections of a garden, X and Y. X: $\text{pH }7.0$ Y: $\text{pH }5.5$ Lime is applied to neutralise the soil in one section of the garden. Which section of the garden should receive the lime, and what is the reason?

Feb/March 2018

An acidic solution is formed when ethanoic acid reacts with water. Which row shows the functions of ethanoic acid and water in this reaction?

Feb/March 2018

The diagram indicates the pH readings for the soil in two sections of a garden, X and Y. X has pH $7.0$. Y has pH $5.5$. Lime is applied to neutralise the soil in one section of the garden. Which section of the garden should receive the lime, and why?

Feb/March 2018

Describe the reactions of hydrochloric acid with: - calcium oxide - magnesium - a named acid-base indicator of your choice.

Feb/March 2018

Limestone rock is composed mainly of calcium carbonate, CaCO$_3$.

Feb/March 2018

Ammonia is a significant chemical substance.

Feb/March 2018

Barium hydroxide is an alkali. It reacts with hydrochloric acid. How does the pH of the hydrochloric acid change as excess aqueous barium hydroxide is added?

Feb/March 2019

The structure of a compound, G, is shown. G belongs to the same homologous series as ethanoic acid. Which row gives some of the properties of an aqueous solution of G?

Feb/March 2019

Aqueous sodium hydroxide acts as a base.

Feb/March 2019

The soil on a farm is acidic. Which substance should the farmer apply in order to neutralise the soil?

Feb/March 2020

Four different acids have been dissolved in water. Which beaker contains the strong acid solution with the greatest concentration?

Feb/March 2020

When zinc carbonate is added to dilute hydrochloric acid, change M occurs. When carbon is heated together with copper(II) oxide, change N occurs. Which row gives the correct description of changes M and N?

Feb/March 2021

What property is exhibited by the alkali sodium hydroxide?

Feb/March 2021

Which of the following statements about strong acids are correct?

Feb/March 2021

Aqueous ammonia behaves as an alkali.

Feb/March 2021

Magnesium powder reacts with an excess of dilute hydrochloric acid to form hydrogen gas. Which of these statements about this reaction are correct?

Feb/March 2023

A water-based solution reacts with a solid. The products formed are an alkaline gas, a salt and water. Which aqueous solution and which solid are involved?

Feb/March 2023

Which substances can react together to produce hydrogen gas?

Feb/March 2023

Which row gives the properties of aqueous ethanoic acid?

Feb/March 2023

Magnesium powder reacts with an excess of dilute hydrochloric acid to form hydrogen gas. Which of the following statements about this reaction are correct?

Feb/March 2023

Butanoic acid dissociates only to a limited extent in aqueous solution. Which row concerning butanoic acid is correct?

Feb/March 2023

Which substances combine to produce hydrogen gas?

Feb/March 2023

Compound X is soluble in water, producing an aqueous solution. Methyl orange is then introduced into the aqueous compound X. The methyl orange becomes red. What is compound X?

Feb/March 2024

Dilute hydrochloric acid reacts with aqueous sodium hydroxide during a neutralisation reaction. Which two ions take part in this neutralisation reaction?

Feb/March 2024

What is the balanced equation for magnesium reacting with dilute sulfuric acid?

Feb/March 2024

Hydrogen iodide is dissolved in water. $\text{HI} \rightarrow \text{H}^+ + \text{I}^-$ Which row shows the end colours observed when the solution is tested using damp red litmus paper and acidified aqueous potassium manganate(VII)?

Feb/March 2024

Which of the following statements about aqueous ethanoic acid are correct?

Feb/March 2024

Which statement gives the properties of hydrochloric acid?

Feb/March 2024

The topic of this question is acids, bases and alkalis. Table 3.1 lists the pH values for several substances.

Feb/March 2024

$\text{HOCl}$ acts as an acid. $\text{NH}_4\text{OH}$ acts as an alkali. Which row gives the ions present in the aqueous solutions that distinguish the acid from the alkali?

Feb/March 2025

A small amount of a solid, E, is placed into a large excess of aqueous ethanoic acid. No gas bubbles are observed and the solid dissolves, producing a colourless solution. What is solid E?

Feb/March 2025

Information about two dilute acids is shown below. Three statements about these acids are given. Which statements are correct?

Feb/March 2025

Which statements are properties of an acid? 1 reacts with ammonium sulfate to produce ammonia 2 changes red litmus to blue

May/June 2016

Which statements describe the properties of an acid?

May/June 2016

Which statements describe properties of an acid?

May/June 2016

Which of the statements describe the properties of an acid?

May/June 2016

Which statements describe the properties of an acid?

May/June 2016

Which of these statements are properties of an acid? 1 reacts with ammonium sulfate to produce ammonia. 2 changes red litmus to blue.

May/June 2016

Hydrochloric acid is placed with magnesium metal and, in a separate test, with sodium carbonate. Which row gives the observations?

May/June 2017

Which statement concerning aqueous ethanoic acid is not correct?

May/June 2017

When compound P is mixed with sodium carbonate, carbon dioxide is given off. When compound Q is mixed with ammonium chloride, ammonia is given off. What are P and Q?

May/June 2017

Which characteristic applies to aqueous ethanoic acid?

May/June 2017

Farmers apply slaked lime (calcium hydroxide) to their fields in order to neutralise soils that are too acidic for crops to grow well. Which ion in slaked lime is responsible for neutralising the acid in the soil?

May/June 2017

Which statement concerning aqueous ethanoic acid is not true?

May/June 2017

Which row compares the hydrogen ion concentration and pH of ethanoic acid with those of hydrochloric acid at the same concentration?

May/June 2017

Which statement concerning sulfuric acid is correct?

May/June 2017

Which of the following statements about a weak acid, such as ethanoic acid, are correct?

May/June 2017

Which statement about sulfuric acid is correct?

May/June 2017

Chloric(I) acid, $\text{HClO}$, is produced when chlorine dissolves in water. It is a weak acid. What does the term weak acid mean?

May/June 2017

Which of the following statements about sulfuric acid is correct?

May/June 2017

When dilute nitric acid is poured onto a solid, F, a gas, G, is given off. This gas is heavier than air and puts out a burning splint. What are F and G?

May/June 2018

Lime is used to treat an industrial waste. Which change happens during the treatment?

May/June 2018

Ammonium nitrate is a widely used fertiliser that farmers apply to raise crop yield. Which compound reacts with ammonium nitrate so ammonia is produced?

May/June 2018

Lime is used to process industrial waste. What change takes place during the treatment?

May/June 2018

Pieces of damp red litmus paper and damp blue litmus paper are put into three separate gas jars. In which gas jars does at least one piece of litmus paper change colour?

May/June 2018

Lime is applied to deal with industrial waste. What change takes place during the treatment?

May/June 2018

The diagram illustrates solid element Q undergoing reaction with an acid and giving off gas R. Which row correctly identifies Q and R?

May/June 2018

Which solution shows the lowest pH?

May/June 2018

A solution containing ethanoic acid, $\text{CH}_3\text{COOH}$, has a concentration of $2\,\text{mol dm}^{-3}$. Which statement about this solution is correct?

May/June 2018

A gas is given off at point X in the apparatus illustrated. Which gas changes the damp Universal Indicator paper to red the fastest?

May/June 2018

Which of the following statements about acids and bases is correct?

May/June 2018

This equation shows an equilibrium involving aqueous ammonia. $\text{NH}_3(aq) + \text{H}_2\text{O}(l) \rightleftharpoons \text{NH}_4^+(aq) + \text{OH}^-(aq)$ In this reaction, what role does aqueous ammonia play?

May/June 2018

Four distinct solutions are tested separately using blue litmus and methyl orange. It is already known that each solution is either acidic or alkaline. The results are given. Which statement is correct?

May/June 2019

Which statements concerning aqueous ethanoic acid are correct?

May/June 2019

What colours are observed when litmus and methyl orange are each added to separate samples of aqueous sodium hydroxide?

May/June 2019

Ammonia gas is formed when compound X is warmed with an ammonium salt. Identify X.

May/June 2019

Which properties does aqueous ethanoic acid have?

May/June 2019

Which row gives the colours shown by litmus and methyl orange in acid and base solutions?

May/June 2019

Which of the following statements about aqueous ethanoic acid is correct?

May/June 2019

Ethanoic acid is classed as a weak acid. Hydrochloric acid is classed as a strong acid. Which of the following statements are correct? 1. Only some ethanoic acid molecules dissociate into ions. 2. The pH of $1.0\,\text{mol/dm}^3$ ethanoic acid is higher than that of $1.0\,\text{mol/dm}^3$ hydrochloric acid. 3. Ethanoic acid is always less concentrated than hydrochloric acid. 4. Ethanoic acid acts as a proton acceptor.

May/June 2019

Which of the following statements about aqueous ethanoic acid are correct?

May/June 2019

Which row indicates the distinction between a weak acid and a strong acid?

May/June 2019

What characteristics does aqueous ethanoic acid possess?

May/June 2019

Acid R and acid S solutions have the same concentration. Equal volumes of each acid, both at the same temperature, are reacted with equal masses of magnesium ribbon. The amount of hydrogen gas produced is measured. The findings are shown. Which statement about the reactions is correct?

May/June 2019

Which statement concerning aqueous ethanoic acid is correct?

May/June 2019

Ethanoic acid is a weak acid, whereas hydrochloric acid is a strong acid. In aqueous solution, both ethanoic acid and hydrochloric acid dissociate.

May/June 2019

Three different tests are done on an aqueous solution of S. The observations are as follows. 1. Magnesium shows no reaction with the solution. 2. When ammonium sulfate is heated with the solution, a gas is released. 3. On addition to the solution, methyl orange becomes yellow. What substance is S?

May/June 2021

Element X makes an oxide, XO, that neutralises sulfuric acid. Which row identifies X and XO?

May/June 2021

The reactions of element M below are shown. When element M is burnt, it forms the oxide of M. This oxide is then dissolved in water to give a solution. On adding blue litmus, the solution turns red. When the oxide is added to purple acidified potassium manganate(VII), the solution becomes colourless. What is the identity of element M?

May/June 2021

When a white solid Z is added to dilute hydrochloric acid, a gas is released. Heating compound Z strongly also produces the same gas. What is Z?

May/June 2021

Which of the following statements about acids is correct?

May/June 2021

A gas is given off at point P in the apparatus shown. Which gas makes the damp universal indicator paper turn red most rapidly?

May/June 2021

In which equation does the underlined reactant behave as a base?

May/June 2021

A gas is given off at point P in the apparatus shown. Which gas causes the damp universal indicator paper to turn red most rapidly?

May/June 2021

When fossil fuels burn, sulfur dioxide is produced and this can cause acid rain. Which ion in rainwater makes it acidic?

May/June 2021

A gas is given off at point P in the apparatus shown. Which gas causes the damp universal indicator paper to turn red most rapidly?

May/June 2021

What products are produced when magnesium hydroxide reacts with hydrochloric acid?

May/June 2022