OCR A-Level Chemistry Periodic table, elements and physical chemistry (01), June 2024: Question 4
1 mark · Easy difficulty · Multiple Choice
Identify which compound of magnesium can be used as an antacid from the given options.
Practise this questionQuestion
Question text
4 Which compounds of magnesium can be used as ‘antacids’?
A Chlorides
B Hydroxides
C Nitrates
D Sulfates
Your answer [1]
Mark scheme
Show the mark scheme
4 B 1
How to answer it
Magnesium Compounds as Antacids
What this question tests
This question tests your factual recall regarding the uses of Group 2 compounds in everyday life—specifically, the application of magnesium hydroxide as a medicinal antacid to neutralise excess stomach acid (hydrochloric acid).
Question 4: Magnesium Compounds as Antacids
✅ Correct Answer
B (Hydroxides)
Magnesium hydroxide ( Mg(OH)₂ ), often sold as 'milk of magnesia', is safely used as an antacid to neutralise excess stomach acid without causing severe side effects.
💡 Key Knowledge
- Antacids are bases that neutralise stomach hydrochloric acid ( HCl ).
- Equation for neutralisation: Mg(OH)₂ + 2HCl -> MgCl₂ + 2H₂O
- Group 2 carbonates (like calcium carbonate) and hydroxides are commonly used as antacids.
🧠 Exam Technique
For factual recall multiple-choice questions, eliminate options that do not make chemical or practical sense. Soluble salts like nitrates or chlorides are rarely used directly as commercial oral antacids for this purpose.
❌ Common Errors
Students sometimes confuse Group 2 solubility trends (which increase down the group) with medical applications, or guess sulfate/chloride salts assuming all metal compounds behave similarly 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, Periodic table, elements and physical chemistry (01), June 2024. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.