Q1. [2] deep thorough-understanding
Metal X displaces metal Y from Y's sulphate solution, but metal Y cannot displace metal Z from Z's sulphate solution, whereas metal X can displace metal Z. Arrange X, Y and Z in decreasing order of reactivity, justifying each step of your reasoning using the concept of displacement reactions.
Generated by claude-sonnet-4-6 · 2026-06-26 01:05 · grounding rag
Model Answer
Since X displaces Y from Y's sulphate solution, X is more reactive than Y.
Since Y cannot displace Z from Z's sulphate solution, Y is less reactive than Z.
Since X can displace Z, X is more reactive than Z.
Decreasing order of reactivity: X > Z > Y
Source: Metals and Non-metals, Activity Series concept; Chapter 1, Displacement Reactions
Explanation
- The key rule: a more reactive metal displaces a less reactive metal from its salt solution (from the activity series concept, Chapter 3).
- Work through each clue logically: X > Y (clue 1), Y < Z (clue 2), X > Z (clue 3).
- This fixes Z between X and Y: X > Z > Y.
- Examiners expect you to state the reasoning for each step, not just the final order — that's where the 2 marks lie.