When ammonia is oxidized with copper oxide, the products formed are copper, nitrogen and water vapour.
3CuO(s)+2NH3(g)→3Cu(s)+N2(g)+3H2O(g)
Ammonia reduces copper oxide to the free metal and itself gets oxidised to nitrogen.
(b) (i) What are the products formed when ammonia is oxidized with copper oxide? (ii) Name one lead compound that can be used to oxidize hydrogen chloride to chlorine.