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

Answer:

the element X is copper because when it is oxidised or left in air it covers itself with a layer of black substance known as copper oxide.

equation for this is : copper + oxygen = copper oxide

Cu+O2=CuO

Answer 2

Answer:

Copper is the brown coloured element X which on heating in air becomes black coloured compound copper oxide.