This deep dive covers Testing for Metal Ions (Cations) 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 2 of 15 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.

🔬 Testing for Metal Ions (Cations)

There are two main approaches to testing for metal cations: flame tests (covered in Topic 48) and adding sodium hydroxide solution to form characteristic precipitates.

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)

Testing for Metal Ions (Cations)