Question

.17: A shiny brown coloured element ‘X’ on heating in air becomes black in colour. Name the element ‘X’ and the black coloured compound formed.

Answer 1

The X element is copper
And the compound is copperoxide

Answer 2

Shiny Brown coloured substance is Copper and

When a Metal React Oxygen , it forms Metallic Oxides or Metal Oxides

Metal + Oxygen -> Metal Oxides

So, Cu ( Copper ) + O2 ( Oxygen ) --> CuO ( Copper Oxide)

Here CuO i.e, Copper Oxide so formed is Black in Colour...

Copper Oxide is the Black Coloured Substabce...