Questions of Effect of Air and Water on Metals - Questions at the end of the chapter - Chapter 4 Class 7 - The World of Metals and Non-metals (Curiosity)

Last updated at July 13, 2026 by

Q9 (Medium): You are provided with three iron nails, each dipped in oil, water and vinegar. Which iron nail will not rust, and why?

Answer:
We have studied that rusting requires both air and water to be present. This is why the oil-dipped nail will not rust.

  • Oil layer prevents air from reaching iron
  • Water and vinegar allow air contact
  • Both air and water are needed for rusting
Iron Nail Rusting Conditions Condition Oil-dipped Nail Water/Vinegar Nails Air contact Blocked by oil Direct contact Water presence No water contact Water present Rusting result No rusting Rusting occurs
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