Difficulty guide
The label describes the problem, not your ability.
1/5 - Foundational
Warm-up setup; checks one basic idea.
2/5 - Routine exam skill
Normal syllabus skill; usually one main rule or interpretation.
3/5 - Standard multi-step
Exam-style problem with multiple steps or a common trap.
4/5 - Hard exam skill
High-end exam problem; combines methods carefully.
5/5 - Challenge
Stretch problem beyond normal exam pressure.
Question
(a) Classify the reaction of quicklime with water. (1 mark)
(b) Write one expected observation when ferrous sulphate crystals are heated strongly. (1 mark)
(c) Write the balanced equation for sodium sulphate solution reacting with barium chloride solution. (2 marks)
(d) Which of the four reactions is a displacement reaction? Give the reason. (2 marks)