Question

A reddish brown metal is heated in the presence of oxygen forms a black compound. on heating the black compound with hydrogen gas , we get back the metal.what are the metal and compound

Answer 1

Reddish brown metal is copper (Cu). When copper is heated in the presence of oxygen, it forms copper(II) oxide (CuO) - the black
compound. Copper (II) oxide can be reduced to metal by heating with hydrogen gas:

CuO + H₂ = Cu + H₂O