1. In general, iron is not used to make body parts of aeroplane. Why? Give any two reasons.
2. In general, iron is not used to make body parts of aeroplane because of the following reasons:
   1. Iron is heavier metal.
   2. It is reactive metal so it reacts with oxygen, water and forms rusts.
3. Write two properties of aluminium that make it suitable for building body parts of the aeroplane.
4. The properties of aluminium that make it suitable for building body parts of the aeroplane are:
   1. It is very light and strong metal.
   2. It does not get rust as air and water don't affect it.
5. The external cover of an aeroplane is made from aluminium instead of iron. Give two reasons.
6. The external cover of an aeroplane is made from aluminium instead of iron because of the following reasons:
   1. Aluminium is lighter than iron.
   2. Iron get rust but aluminium doesn't get rust.
7. Identify the metals obtained from the following ores.
8. Bauxite = Aluminium (Al)
   Silver copper glance = Silver (Ag)
   Magnetite = Iron (Fe)
   Chalcopyrite = Copper (Cu)
9. Write two uses of metal obtained from argentite.
10. Two uses of metal obtained from argentite are:
    1. Silver is used to make jewellery, coins and decoratives articles.
    2. It is used to make mirrors as it is the best reflector of visible light.
11. Copper is used to make elctrical wire, why? Give two reasons. How aquaregia is prepared?
12. Copper is used to make elctrical wire because of the follwing reasons:
    
    1. It is very good conductor of electricity.
    2. It is ductile and has high melting point (1083°C).
    Aquaregia is prepared by mixing conc. hydrochloric acid (HCl) and conc. nitric acid (HNO₃) in the ratio of 3:1.
13. Gold is found is pure state but not the iron, why?
14. Iron rusts when it comes in contact with oxygen but gold almost reacts with nothing. So, Gold is found in the pure state but not iron.
15. Why is gold called noble metal?
16. Gold is called noble metal because of its stability and it does not react with other metals.