Question

when the powder of a common metal is heated in an open china dish, its colour turns black.however when hydrogen is passed to the black hot substance so formed,it regains its orginal colour.name the metal initially taken in the powder form.write balanced chemical equations for both reactions

Answer 1

Heating up of the metal in an open china dish results in the formation of metal oxide i.e. gain of oxygen by the metal, so it is an oxidation reaction.

The metal taken in the powdered form is Copper(Cu)

4Cu +O2 -----heat-----> 2Cu2O(black)

Cu2O + H2 ------------------> 2Cu + H2O