A reddish brown coloured metal is used in electrical wires. When powdered and heated strongly in an open china dish, its colour turns black. When hydrogen gas is passed over this black substance, it regains its original colour. Based on the above information, answer the following question.
(i) Name the metal and the black coloured substance formed.
(ii) Write balanced chemical equations for both the reactions.

X is a reddish - brown metal used in electrical wires. When the same metal in powdered form is heated strongly, it turns black. When hydrogen gas is passed over this black substance it regains its original colour. The metal X is

When the powder of a common metal is heated in an open china dish, colour turns black. However, when hydrogen gas is passed over the hot black substance formed, it regains its original colour. Based on this information, answer the following questions : (i) What type of chemical reaction takes place in each of the two given steps ? (ii) Name the metal initially taken in the powder form. Write balanced chemical equations for both these reactions.

The black coloured substance formed when copper is heated in presence of oxygen.