This comparison covers All Ion Tests: Full Reference 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 topic appears regularly enough that it should still be part of a steady revision cycle. It is section 6 of 14 in this topic. Use this comparison to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 6 of 14
Practice
20 questions
Recall
14 flashcards
⚖️ All Ion Tests: Full Reference
| Ion | Reagent | Positive Result | Key Equation |
|---|---|---|---|
| Cu²⁺ | NaOH(aq) | Blue precipitate | Cu²⁺ + 2OH⁻ → Cu(OH)₂(s) |
| Fe²⁺ | NaOH(aq) | Green precipitate | Fe²⁺ + 2OH⁻ → Fe(OH)₂(s) |
| Fe³⁺ | NaOH(aq) | Brown/orange precipitate | Fe³⁺ + 3OH⁻ → Fe(OH)₃(s) |
| Al³⁺ | NaOH(aq) | White precipitate; redissolves in excess | Al³⁺ + 3OH⁻ → Al(OH)₃(s) |
| Ca²⁺ | NaOH(aq) | White precipitate (stays) | Ca²⁺ + 2OH⁻ → Ca(OH)₂(s) |
| CO₃²⁻ | Dilute HCl | Fizzing; gas turns limewater milky | CO₃²⁻ + 2H⁺ → CO₂ + H₂O |
| SO₄²⁻ | BaCl₂ + HCl | White precipitate of BaSO₄ | Ba²⁺ + SO₄²⁻ → BaSO₄(s) |
| Cl⁻ | AgNO₃ + HNO₃ | White precipitate of AgCl | Ag⁺ + Cl⁻ → AgCl(s) |
| Br⁻ | AgNO₃ + HNO₃ | Cream precipitate of AgBr | Ag⁺ + Br⁻ → AgBr(s) |
| I⁻ | AgNO₃ + HNO₃ | Yellow precipitate of AgI | Ag⁺ + I⁻ → AgI(s) |