Describe an activity to show a displacement reaction between iron and copper sulphate. Write the equation and your observations.

1. 1 · Define in one line. In a displacement reaction, a more reactive element displaces a less reactive element from its compound.
2. 2 · Describe the activity.
   • Clean two iron nails with sandpaper.
   • Dip one nail in copper sulphate solution for about 20 minutes; keep the other to compare.
3. 3 · Draw the set-up. Draw a test tube with an iron nail hanging by a thread in blue solution, beside a dry nail. Label: iron nail, thread, copper sulphate solution.
4. 4 · Write observations and the equation. A brown coat forms on the nail; the blue solution turns pale green. Fe(s) + CuSO₄(aq) → FeSO₄(aq) + Cu(s).
5. 5 · Link to real life. Copper sulphate crop spray is not mixed in iron buckets, because iron would displace the copper.
6. 6 · Close in one line. So iron is more reactive than copper.

Scoring tip: Mention both changes: the coat on the nail and the colour of the solution. Examiners look for "brown" and "pale green".