Question

A shiny brown substance x on heating in air turns black and a new substance y is formed name the substance x and black compound y

Answer 1

substance x is cupper
compound form after reaction y is CuO

Answer 2

Answer:

The shiny brown substance X is Copper (Cu)

And the new substance Y is Copper Oxide (CuO)

2$Cu + O_{2}$ ⇒ 2CuO