A reddish brown coloured metal, used in electrical wires, when powdered and heated strongly in an open china dish, its colour turns black. When hydrogen gas in passed over this black substance, it regains its original colour. Based on the above information answer the following questions.
i. Name the metal and the black coloured substance formed.
ii. Write balanced chemical equations for both the reactions.
(i) The brown colour metal is copper (Cu) and black coloured substance is Copper oxide (CuO).
(ii) (a) When Cu metal is heated in an open china dish then Cu metal gets oxidised
Cu + O2→ 2CuO
(b) When hydrogen gas is passed over the black substance then CuO gets reduced
CuO + H2→ Cu + H2O