Classify Physical/Chemical Change: Fe + CuSO4 MCQs Quiz | Class 9

This quiz covers the observation-based classification of the reaction between iron and copper sulphate solution for Class IX Science (Code 086), Unit Practicals (Unit I). Students will test their understanding of the color changes, deposits formed, and the type of chemical reaction involved. Submit your answers to check your score and download the solution PDF for revision.

Overview of the Reaction

The reaction between iron nails and copper sulphate solution is a classic example of a single displacement reaction. In this chemical change, iron (Fe) is more reactive than copper (Cu) and displaces it from its salt solution.

Chemical Equation:
Fe(s) + CuSO4(aq) → FeSO4(aq) + Cu(s)

Key Observations

  • Initial State: The copper sulphate solution is blue in color. The iron nail is greyish-metallic (silver-grey).
  • Reaction Process: As the nail is kept in the solution for about 15-30 minutes, a reaction occurs at the surface of the iron.
  • Final State: The blue color of the solution fades and turns into a light pale green color due to the formation of ferrous sulphate (Iron(II) sulphate).
  • Deposit: A reddish-brown coating of copper metal is deposited on the iron nail.

Comparison Table

Property Before Reaction After Reaction
Solution Color Blue (CuSO4) Pale Green (FeSO4)
Iron Nail Greyish/Metallic Reddish-brown coating
Substance Reactants Products

Why is it a Chemical Change?

This process is classified as a chemical change because:

  1. New substances (Iron sulphate and Copper) are formed with different properties.
  2. The change involves a permanent alteration in chemical composition.
  3. Energy changes usually accompany the reaction.
  4. The original reactants cannot be recovered by simple physical means.

Extra Practice Questions

  • 1. Why should the iron nail be cleaned with sandpaper before the experiment?
  • 2. What would happen if a silver coin were used instead of an iron nail? Why?
  • 3. Is the reaction exothermic or endothermic?
  • 4. Can we store copper sulphate solution in an iron container? Explain.
  • 5. Write the ionic equation for the reaction between iron and copper sulphate.