What happens when:
(i) Lead is heated to 400–500°C in air.
(ii) Steam is passed over heated iron.
(iii) Copper oxide is heated with magnesium.
(iv) Aluminium wire is dipped in heating water.
(iii) On heating with magnesium, copper oxide is reduced to the copper metal. Since magnesium is more reactive than copper thus it replace copper form its oxide.
CuO + Mg → MgO + Cu
(iv) In boiling water, aluminium forms aluminium hydroxide and H2 gas is liberated.
Al + 3H2O → Al(OH)3 + 3H2
