This memory aid covers Memory Aid 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 10 of 15 in this topic. Use it for quick recall, then test yourself straight afterwards so the memory aid becomes usable in an answer.
🧠 Memory Aid
"NaOH for METALS, BaCl₂ for SULFATES, AgNO₃ for HALIDES"
Precipitate colours with NaOH: "Cu = Blue, Fe2 = Green, Fe3 = Brown, Al/Ca = White"
Silver halide colours: "White, Cream, Yellow — going down the halogen group"
- Cl⁻ = White
- Br⁻ = Cream
- I⁻ = Yellow
- Remember: "Why (Y) does Cream come between?" — White, Cream, Yellow
Quick Check: A solution gives a brown precipitate when sodium hydroxide is added. What metal ion is present?
Iron III ion (Fe³⁺). It forms brown/orange Fe(OH)₃ precipitate with sodium hydroxide.
Practice questions for Tests for Ions
Which reagents are used to test for carbonate ions in a solution?
Describe how sodium hydroxide solution can be used to distinguish between iron(II) ions and iron(III) ions in solution, including the expected observations.