Some reactions of the halide ions: past paper questions

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• Question 21May/June 2026, paper 11Multiple choice1 mark

  Which statement is correct?

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• Question 21Oct/Nov 2025, paper 11Multiple choice1 mark

  Equation 1 and equation 2 show two different reactions of halide ion ${\text{Q}}^{-}$ with concentrated sulfuric acid.

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• Question 21Oct/Nov 2024, paper 11Multiple choice1 markHas a diagram

  In reaction 1, concentrated sulfuric acid is added to potassium chloride and the fumes produced are bubbled into aqueous potassium iodide solution. In reaction 2, potassium chloride is dissolved in aqueous ammonia and this is then added to aqueous silver nitrate.

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• Question 23Oct/Nov 2023, paper 11Multiple choice1 mark

  Which statement about the halogens or halide ions is correct?

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• Question 23May/June 2026, paper 11Multiple choice1 mark

  Halide ion ${\text{X}}^{-}$ reacts with concentrated sulfuric acid. Among the products of the reaction is a sulfur-containing compound in which the oxidation number of the sulfur is $-2$. Which halide ion is ${\text{X}}^{-}$?

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• Question 22Oct/Nov 2025, paper 12Multiple choice1 mark

  $\text{X}$ and $\text{Y}$ are sodium salts of Group 17 elements. When $\text{X}$ reacts with concentrated sulfuric acid, hydrogen sulfide, ${\text{H}}_2\text{S}$, is produced.

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• Question 22Oct/Nov 2024, paper 12Multiple choice1 markHas a diagram

  The colours of the silver halides $\mathrm{A}\mathrm{g}\mathrm{C}\mathrm{l}$, $\mathrm{A}\mathrm{g}\mathrm{B}\mathrm{r}$ and $\mathrm{A}\mathrm{g}\mathrm{I}$ differ. The solubilities of these halides in aqueous ammonia also differ. Which row is correct?

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• Question 25Oct/Nov 2023, paper 12Multiple choice1 mark

  When concentrated sulfuric acid is added to solid sodium chloride, $\text{HCl}$ is formed but not ${\text{Cl}}_2$. When concentrated sulfuric acid is added to solid sodium iodide, ${\text{I}}_2$ is formed. Which statement explains these observations?

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• Question 22May/June 2026, paper 13Multiple choice1 mark

  Concentrated sulfuric acid is added to $\text{KX(s)}$, where X is Br, Cl or I. The element sulfur and the halogen molecule, ${\text{X}}_2$, are two of the products made in this reaction. What is the colour of ${\text{X}}_2$ in the gaseous state?

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• Question 3May/June 2026, paper 21Structured10 marks

  Separate samples of $\mathrm{N}\mathrm{a}\mathrm{C}\mathrm{l}$, $\mathrm{N}\mathrm{a}\mathrm{B}\mathrm{r}$ and $\mathrm{N}\mathrm{a}\mathrm{I}$ each react with concentrated ${\mathrm{H}}_2{\mathrm{S}\mathrm{O}}_4$. Table 3.1 shows the observations for each reaction.

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• Question 20May/June 2025, paper 12Multiple choice1 markHas a diagram

  Sodium bromide is warmed with concentrated sulfuric acid. Which row describes the change in the oxidation number of the sulfur and the role of the bromide ions in the reaction?

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• Question 17May/June 2023, paper 11Multiple choice1 mark

  The solids sodium chloride and sodium iodide both react with concentrated sulfuric acid at room temperature. With $\mathrm{N}\mathrm{a}\mathrm{C}\mathrm{l}$, the products are $\mathrm{N}\mathrm{a}\mathrm{H}\mathrm{S}{\mathrm{O}}_4$ and $\mathrm{H}\mathrm{C}\mathrm{l}$.

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• Question 3May/June 2026, paper 22Structured8 marks

  Separate samples of $\mathrm{N}\mathrm{a}\mathrm{C}\mathrm{l}$ and $\mathrm{N}\mathrm{a}\mathrm{B}\mathrm{r}$ are reacted with concentrated ${\mathrm{H}}_2\mathrm{S}{\mathrm{O}}_4$. Table 3.1 shows the observations for each reaction. Write an equation for reaction 1.

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• Question 17May/June 2025, paper 13Multiple choice1 mark

  Mixing aqueous silver nitrate and aqueous sodium chloride produces a precipitate. Addition of which reagent to the mixture gives a colourless solution?

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• Question 22May/June 2024, paper 11Multiple choice1 mark

  Compound Q dissolves in water. $\text{Q(aq)}$ does not react with dilute sulfuric acid. $\text{Q(aq)}$ forms a precipitate when aqueous silver nitrate is added.

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• Question 22May/June 2023, paper 12Multiple choice1 mark

  J dissolves in water to give an aqueous solution K. K gives a dense white precipitate when aqueous silver nitrate is added.

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• Question 1May/June 2026, paper 23Structured12 marks

  The chlorides of Period 3 elements show different physical and chemical properties.

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• Question 21May/June 2024, paper 12Multiple choice1 markHas a diagram

  The table shows statements about some of the properties of halogens and their compounds and explanations for these properties. Which row shows a correct statement about the property and a correct explanation for the statement?

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• Question 24May/June 2023, paper 13Multiple choice1 mark

  Which statement about the halogens is correct?

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• Question 25May/June 2023, paper 13Multiple choice1 mark

  When concentrated sulfuric acid is added to solid sodium bromide, bromine gas is produced, along with a number of other products. However, when concentrated sulfuric acid is added to solid sodium chloride, only hydrogen chloride and sodium hydrogensulfate are produced.

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• Question 1May/June 2024, paper 21Structured10 marks

  The elements of Group 17 are called halogens. Complete Table 1.1.

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• Question 4May/June 2023, paper 23Structured10 marks

  Hydrogen chloride gas is made in the laboratory by adding concentrated sulfuric acid to potassium chloride. Construct an equation for this reaction.

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