(a) because aluminium is a soft malleable metal. it can be made to in sheets to form thin wrapping sheets. also, it does not react with food items.
(b) because metals are good conductors of heat and electricity. the immersion rod needs electric supply to get heated and to heat liquids.
(c) they're kept in kerosene to keep them from coming in contact with oxygen and moisture as they react to form their hydroxides.
4. Magnesium is a metal. Metals react with oxygen to form metallic oxides. So Magnesium oxides are basic in nature. But nonmetals react with oxygen to form nonmetallic oxides. These oxides differ from metallic oxides because they are acidic in nature. Nonmetallic oxides react with water to form acids. Therefore, Sulphur dioxide is acidic in nature. Magnesium oxide is basic in nature.
5. Copper forms a green deposit on its surface when exposed to air which is usually a mixture of copper carbonate and copper hydroxide. It's acidic in nature.
Sodium metal reacts with chlorine gas to form sodium chloride. Sodium is in solid state, chlorine is in gaseous state and Sodium chloride is in solid state.
In the chemical reaction, sodium and chlorine are reactants while sodium chloride is the product.
Additionally the chemical reaction above is balanced so as to obey the law of conservation of mass.
