Question

4. A metal “X” when heated in presence of Oxygen it forms a black

substance “Y”. If hydrogen gas is passed over this heated material “Y” , the

black coating on the surface turns brown as the reverse reaction takes place

and “X” is obtained.

a) Find out the substance “X”& “Y”​

Answer 1

Answer:

The substance X is copper. On heating in air, it forms copper oxide Y.

2Cu + O2 –> 2CuO

(copper. (copper

Powder) oxide

(Brown) black

(X) (Y)

When hydrogen gas is passed over black copper oxide then it turns brown as oxygen is removed by hydrogen.

CuO+H2–>Cu +H2O