Question 11 — One of the methods of protecting - Questions at the end of the chapter - Chapter 4 Class 7 - The World of Metals and Non-metals (Curiosity)

Last updated at August 17, 2026 by

Q11 (Difficult): One of the methods of protecting iron from getting rusted is to put a thin coating of zinc metal over it. Since sulphur does not react with water, can it be used for this purpose? Justify your answer.

Answer:
We have studied that rusting prevention requires blocking both air and water from reaching iron . This is why sulphur cannot replace zinc coating.

  • Zinc coating reacts with air to form protective layer
  • Sulphur is a non-metal and cannot form metallic coating
  • Sulphur is brittle and will break when iron bends
  • Zinc is malleable and stays attached to iron surface
  • Sulphur does not bond strongly with iron metal

Conclusion: Sulphur cannot replace zinc because it lacks metallic properties needed for protective coating .

Zinc vs Sulphur for Iron Protection Property Zinc Coating Sulphur Coating Material type Metal - malleable Non-metal - brittle Bonding with iron Strong metallic bond Weak attachment Flexibility Bends with iron Breaks when bent Protective layer Forms stable coating Cannot form coating Effectiveness Prevents rusting Cannot prevent rusting
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