(i) Platinum. gold and silver are used to make jewellerv because of their bright shinv surface and high resistance to corrosion. Also, thev have high nralleability and ductility.
(b) Sodium. potassium and lithium are stored under oil to prevent their reaction with oxygen, moisture and carbon dioxide of air so as to protect them because they are very reactive metals.
(c) Aluminium metal forms a thin layer of aluminium oxide all over its surface, under the action of moist air. This layer prevents the metal underneath from further corrosion. It is cheap, easily available, malleable, ductile and a good conductor of heat. Therefore, it is used to make utensils for cooking.
(d) It is easier to obtain a metal from its oxides as compared to its sulphides and carbonates. So, prior to reduction, metal carbonate and sulphides must be converted into metal oxides. A carbonate ore is converted into oxide by calcination, whereas a sulphide ore is converted into oxide by roasting.
