1 Compound A is a chloride of a Period 3 element.
A student carries out the 2 steps below to find the formula of compound A.
Step 1 The student adds 5.00 × 10–4 mol of compound A to water.
A colourless solution is formed.
Step 2 The colourless solution reacts with exactly 60.0 cm3 of 2.50 × 10–2 mol dm–3 AgNO3(aq) to form a white
precipitate.
i. Write an ionic equation, with state symbols, for the reaction in Step 2.
[1]
ii. Determine the formula of compound A.
formula of A = ................................................... [3]
2 In the UK, water companies typically treat drinking water with chlorine gas at a concentration of 0.500 mg dm-3 or
less.
Which statement about UK drinking water is correct?
A Chlorine in drinking water can catalyse the breakdown of ozone.
B Chlorine may form toxic chlorinated hydrocarbons.
C Drinking water with a chlorine gas concentration of 0.500 mg dm–3 contains 2.12 × 1018 chlorine molecules
in each dm3.
D In hot weather, chlorine can vaporise from drinking water to cause global warming.
Your answer [1]
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, 3 Which reaction does not show disproportionation of chlorine?
A MnO2 + 4HCl → MnCl2 + Cl2 + 2H2O
B Cl2 + H2O → HCl + HClO
C 2ClO2 + 2NaOH → NaClO2 + NaClO3 + H2O
D 2NaOH + Cl2 → NaCl + NaClO + H2O
Your answer [1]
4 Chlorine has many uses.
i. Chlorine is used to treat water in large-scale water treatment plants.
Suggest why chlorine is added to water in large-scale water treatment plants.
[1]
ii. Sea water contains aqueous bromide ions.
Chlorine is used to extract bromine from sea water.
Construct the ionic equation for this reaction and explain why chlorine is suitable for this extraction of
bromine but iodine is not.
Equation
Explanation
[2]
5 Which equation does not represent a disproportionation reaction?
A Cl2 + H2O → HClO + HCl
B Cl2 + 2NaOH → NaClO + NaCl + H2O
C 4KClO3 → KCl + 3KClO4
D 4HCl + MnO2 → MnCl2 + Cl2 + 2H2O
Your answer [1]
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, 6 Which statement explains the trend in boiling points down the halogens group?
A The bond enthalpy of the covalent bonds increases.
B The halogens become less electronegative.
C The induced dipole-dipole interactions (London forces) become stronger.
D The reactivity of the halogens decreases.
Your answer [1]
7 This question is about the first 36 elements in the periodic table:
From these 36 elements only, write the symbol for the element(s) that fit each description.
The element that forms 1– ions most readily
................... [1]
8 Which statement explains the trend in boiling points down the halogens group?
A Covalent bonds become stronger.
B Induced dipole–dipole interactions (London forces) become stronger.
C Ionic bonds become stronger.
D Permanent dipole–dipole interactions become stronger.
Your answer [1]
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, 9(a) This question is about halogens and halogen compounds.
Seawater contains very small quantities of dissolved iodide ions.
The concentration of potassium iodide, KI, in seawater is 0.150 g dm–3.
Iodine can be extracted by bubbling chlorine gas through seawater.
Explain why chlorine is more reactive than iodine and determine the volume, in dm3, of seawater that is needed
to manufacture 1.00 tonne of iodine, I2.
[6]
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A student carries out the 2 steps below to find the formula of compound A.
Step 1 The student adds 5.00 × 10–4 mol of compound A to water.
A colourless solution is formed.
Step 2 The colourless solution reacts with exactly 60.0 cm3 of 2.50 × 10–2 mol dm–3 AgNO3(aq) to form a white
precipitate.
i. Write an ionic equation, with state symbols, for the reaction in Step 2.
[1]
ii. Determine the formula of compound A.
formula of A = ................................................... [3]
2 In the UK, water companies typically treat drinking water with chlorine gas at a concentration of 0.500 mg dm-3 or
less.
Which statement about UK drinking water is correct?
A Chlorine in drinking water can catalyse the breakdown of ozone.
B Chlorine may form toxic chlorinated hydrocarbons.
C Drinking water with a chlorine gas concentration of 0.500 mg dm–3 contains 2.12 × 1018 chlorine molecules
in each dm3.
D In hot weather, chlorine can vaporise from drinking water to cause global warming.
Your answer [1]
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, 3 Which reaction does not show disproportionation of chlorine?
A MnO2 + 4HCl → MnCl2 + Cl2 + 2H2O
B Cl2 + H2O → HCl + HClO
C 2ClO2 + 2NaOH → NaClO2 + NaClO3 + H2O
D 2NaOH + Cl2 → NaCl + NaClO + H2O
Your answer [1]
4 Chlorine has many uses.
i. Chlorine is used to treat water in large-scale water treatment plants.
Suggest why chlorine is added to water in large-scale water treatment plants.
[1]
ii. Sea water contains aqueous bromide ions.
Chlorine is used to extract bromine from sea water.
Construct the ionic equation for this reaction and explain why chlorine is suitable for this extraction of
bromine but iodine is not.
Equation
Explanation
[2]
5 Which equation does not represent a disproportionation reaction?
A Cl2 + H2O → HClO + HCl
B Cl2 + 2NaOH → NaClO + NaCl + H2O
C 4KClO3 → KCl + 3KClO4
D 4HCl + MnO2 → MnCl2 + Cl2 + 2H2O
Your answer [1]
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, 6 Which statement explains the trend in boiling points down the halogens group?
A The bond enthalpy of the covalent bonds increases.
B The halogens become less electronegative.
C The induced dipole-dipole interactions (London forces) become stronger.
D The reactivity of the halogens decreases.
Your answer [1]
7 This question is about the first 36 elements in the periodic table:
From these 36 elements only, write the symbol for the element(s) that fit each description.
The element that forms 1– ions most readily
................... [1]
8 Which statement explains the trend in boiling points down the halogens group?
A Covalent bonds become stronger.
B Induced dipole–dipole interactions (London forces) become stronger.
C Ionic bonds become stronger.
D Permanent dipole–dipole interactions become stronger.
Your answer [1]
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, 9(a) This question is about halogens and halogen compounds.
Seawater contains very small quantities of dissolved iodide ions.
The concentration of potassium iodide, KI, in seawater is 0.150 g dm–3.
Iodine can be extracted by bubbling chlorine gas through seawater.
Explain why chlorine is more reactive than iodine and determine the volume, in dm3, of seawater that is needed
to manufacture 1.00 tonne of iodine, I2.
[6]
© OCR 2025. You may photocopy this page. 4 of 48 Created in ExamBuilder
