Answer to Question #68601 in General Chemistry for farisa

Question

i am doing a science experiment on how different liquids affect the corrosion rates on a steel nail in water and salt water. After a couple days the nail had a orange substance layered on it ( i thought it was rust). By day 7 it would layer on the nail and fall off ( wasn't stuck on). when i weighed the nails they don't drop by much in mass ( 0.04 g ) . most of the substance fell off and collected at the bottom . What do you think the orange substance on the nails were? how did it form?

i also want to ask what the chemical formula of corrosion with steel ? and what metals are steel made out of?

Answer 1

Steel is an alloy that consists of iron and carbon, iron is subjected to corrosion
4Fe+3O₂+2H₂O->2Fe₂O₃*H₂O
Fe₂O₃*H₂O- Rust formula
In the solution, the destruction of iron occurs faster
If the acid medium
Anode Fe-3e->Fe³⁺
Cathode 2H⁺+2e->H₂
If the alkaline medium
Anode Fe – 2e>Fe³⁺
Cathode O₂+2H₂O+4e>4OH⁻
Brown plaque is rust but its mass is small it needs a lot of time for a noticeable.