Question

What do you observe when:

Black copper oxide is heated with charcoal.

Answer 1

• Copper oxide (black) when heated with charcoal turns brown.
• The change of the colour results due to the reduction of copper oxide by the carbon (coke)

$\mathrm{CuO}\left(\mathrm{s}\right)+\mathrm{C}\left(\mathrm{s}\right)\to \mathrm{Cu}\left(\mathrm{s}\right)+\mathrm{CO}\left(\mathrm{g}\right)$

(Black) (charcoal) (Reddish brown)

When Black cupper oxide is heated with charcoal it changes into Reddish brown.