Case study·Standard multi-step (3/5)·No calculator
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 student balances an ionic redox equation and gets equal atoms on both sides, but the total charge is +3 on the left and +1 on the right.
Total: 4 marks
(a) Is the equation fully balanced? (1 mark)
(b) What condition is still violated? (2 marks)
(c) Which species is normally used to repair charge balance in half-reactions? (1 mark)
Something wrong with this item?