If a hot water pipe is made of copper, and a boiler is made of iron, which metal would corrode first? And why? Please help, thank you.
Don't usually do homework questions......... They both will oxidize quickly. The iron will corrode first for two reasons, only one of which is probably your answer. Iron oxidizes in oxygen readily, but copper does not, or not so much. It's sulfur that's the main culprit in copper corrosion (in the atmosphere). But your answer is that as iron corrodes, it creates flakes of iron oxide, which fall away leaving fresh metal exposed to the air. Gradually it will just eat right through an iron sheet. It's a fairly unique property that iron has - most other metals don't do that.