This exam focus covers Exam Focus 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 12 of 14 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
Topic position
Section 12 of 14
Practice
20 questions
Recall
14 flashcards
🎯 Exam Focus
Very High Frequency
What Examiners Ask About Ion Tests
- "Describe tests to identify the ions present in an unknown compound" — state reagent and expected result for each test (4–6 marks)
- "Explain why dilute HCl is added before BaCl₂" — prevents false positive from carbonate ions (2 marks)
- "What colour precipitate forms when NaOH is added to Fe²⁺?" — green (1 mark)
- "How would you distinguish Al³⁺ from Ca²⁺?" — add excess NaOH; only Al(OH)₃ redissolves (2 marks)
- Write ionic equations for precipitation reactions (2 marks)
- "A student observes a yellow precipitate with AgNO₃/HNO₃. Which halide is present?" — iodide (1 mark)