If you leave a piece of iron in the open for a few days, it acquires a film of brownish substance, called rust. Do you think rust is different from iron?

[AmarCBSE]

If you leave a piece of iron in the open for a few days, it acquires a film of brownish substance, called rust.

1. Do you think rust is different from iron?
2. Can you change rust back into iron by some simple methods?
3. Do you think formation of rust from iron is a chemical change?
4. Give two other examples of a similar type of change.

Answer:

1. Yes, rust is chemically different from iron.
2. No
3. Yes, it is a chemical change.

• Setting of curd from milk.
• Burning of magnesium ribbon to form magnesium oxide.