Chemistry · May / June 2017 · Paper 11 · Question 30

After the collapse of a river bridge, a new car was immersed in the river water for several months. When it was recovered, the parts of the car made of steel, an alloy of iron, were found to be corroded. The parts made of aluminium were not corroded. Which statement explains these differences in corrosion?

1. AAluminium has a coating of aluminium oxide.
2. BAluminium has a very low density.
3. CAluminium is an excellent conductor of electricity.
4. DAluminium is less reactive than iron.

As printed in the paper