2Fe(s) + 3O2(g) à Fe2O3(s)
We showed this reaction using iron nails in water. Most nails come with a galvanized coating to prevent rusting. On half the nails this was removed by soaking in 12M HCl. The nails were washed and sanded lightly to remove any coating of rust. One nail with anti-rust coating and one without were placed in beakers containing ~400mL distilled water, tap water, boiled tap water, 1M NaCl, or 1M HCl.
The nails in 1M NaCl rusted the most, followed by tap water, then boiled tap water. The nails in the distilled water rusted the least. The nails in 1M HCl didn’t form Fe2O3, they caused the solution to turn green. This showed that removing impurities and oxygen from the water slowed the rate of oxidation.
Chemical Used Amount Cost
NaCl ~30g ~$0.06
HCl ~40mL ~$4.70
Total cost of experiment $4.76.