Question

Rust forming on a piece of iron is an example of which of the following? *

1The natural process of decay as metallic ions age
2 A physical change because the process can be reversed
3 A chemical change because oxygen atoms from the atmosphere bonded with the iron atoms
4 A violation of the laws of physics because new mass has been created​

Answer 1

Rust is an iron oxide and formed by the reaction of iron and oxygen in the presence of moisture. So the answer would be C