Chemical AnalysisExam Tips

Exam Tips for Ion Tests

Part of Tests for Ions · GCSE GCSE Chemistry revision

This exam tips covers Exam Tips for Ion Tests within Tests for Ions for GCSE Chemistry. Revise Tests for Ions in Chemical Analysis for GCSE Chemistry with 20 exam-style questions and 14 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 14 of 15 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.

Topic position

Section 14 of 15

Practice

20 questions

Recall

14 flashcards

💡 Exam Tips for Ion Tests

🎯 Common Question Types:

Identify ions from given test results (1 mark each)
Describe tests to confirm presence of named ions (2–3 marks)
Explain why acid must be added before BaCl₂ or AgNO₃ (2 marks)
Write ionic equations for precipitation reactions (2 marks)
Distinguish between similar ions (e.g. Al³⁺ vs Ca²⁺) (2 marks)

📝 Key Command Words:

Describe: State reagent added AND expected observation
Identify: Name the ion from given observations
Explain: Give the chemical reason (e.g. why acid is added)
Write the ionic equation: Include state symbols (aq), (s)

⚠️ Common Mistakes to Avoid:

Forgetting acid in BaCl₂ and AgNO₃ tests — always acidify first
Confusing Fe²⁺ (green) and Fe³⁺ (brown) — green = iron II, brown = iron III
Saying "white precipitate" for Al³⁺ without mentioning it redissolves in excess
Mixing up silver halide colours — white (Cl⁻), cream (Br⁻), yellow (I⁻)
Not giving state symbols in ionic equations

Keep building this topic

Read this section alongside the surrounding pages in Tests for Ions. That gives you the full topic sequence instead of a single isolated revision point.

Exam Focus Knowledge Organiser: Ion Tests The Detective's Chemistry Toolkit Testing for Metal Ions (Cations)

Practice Questions for Tests for Ions

Which reagents are used to test for carbonate ions in a solution?

A. Add barium chloride solution, then dilute HCl
B. Add dilute acid, then test the gas with limewater
C. Add silver nitrate solution, then dilute HNO3
D. Add sodium hydroxide solution and warm

1 markfoundation

Describe how sodium hydroxide solution can be used to distinguish between iron(II) ions and iron(III) ions in solution, including the expected observations.

3 marksstandard

Quick Recall Flashcards

How do you test for sulfate ions (SO₄²⁻)?

Add barium chloride solution + dilute HCl. White precipitate of BaSO₄ forms. Equation: Ba²⁺ + SO₄²⁻ → BaSO₄(s)

What is a precipitation reaction?

A reaction where two soluble ionic compounds react to form an insoluble precipitate. General form: A⁺(aq) + B⁻(aq) → AB(s)

20 questions on Tests for Ions — practise free

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Exam Focus

Knowledge Organiser: Ion Tests