OCR A-Level Chemistry AS Breadth in chemistry (01), June 2024: Question 7

1 mark · Easy difficulty · Multiple Choice

Identify which Group 2 compound is not suitable for neutralising acid soils or treating indigestion from a multiple-choice list.

Practise this question

Question

Multiple choice question 7 asking which Group 2 compound is not suitable for use in agriculture to neutralise acid soils or in medicine to treat indigestion. Four options are given: A, Mg(OH)2; B, MgSO4; C, CaCO3; and D, CaO. An empty box is provided for the answer, with [1] mark indicated on the right.
Question text

7 Group 2 compounds can be used in agriculture to neutralise acid soils and in medicine to treat

indigestion.

Which Group 2 compound is not suitable for either use?

A Mg(OH)2

B MgSO4

C CaCO3

D CaO

Your answer [1]

Mark scheme

Show the mark scheme Mark scheme showing the correct answer for question 7 as B, awarding 1 mark.

7 B 1

How to answer it

Uses of Group 2 Compounds

What this question tests

This question assesses your factual recall and understanding of the practical applications of Group 2 compounds, specifically their role as bases used to neutralise acids in agriculture (treating acidic soil) and medicine (indigestion tablets).

Question Part 7

Neutralisation Properties of Group 2 Compounds

✅ Correct Answer

B ( MgSO₄ )

Mark allocated: 1 mark

💡 Key Knowledge

  • To neutralise acids (which are corrosive or cause discomfort), a Group 2 compound must act as a base (such as an oxide, hydroxide, or carbonate).
  • MgSO₄ (magnesium sulfate) is a salt, not a base. It is neutral and cannot neutralise acid soils or stomach acid.
  • Mg(OH)₂ and CaCO₃ are widely used as mild antacids in medicine.
  • CaO (quicklime) and CaCO₃ (limestone) are routinely added to agricultural land to raise soil pH.

🧠 Exam Technique

Read the stem carefully and spot the negative qualifier: not suitable. Eliminate options that you know are bases used for neutralisation ( Mg(OH)₂ , CaCO₃ , CaO forms Ca(OH)₂ in moist soil), leaving you with the neutral salt.

❌ Common Errors

Students sometimes confuse magnesium sulfate ( MgSO₄ , Epsom salts) with magnesium hydroxide ( Mg(OH)₂ , milk of magnesia) and incorrectly assume all magnesium compounds can be used interchangeably in medicine.

Topics

Module 3: Periodic table and energy · 3.1 The periodic table

Question and mark scheme from the OCR A-Level Chemistry examination, AS Breadth in chemistry (01), June 2024. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.