The colour formed when the hydrogen gas is passed over heated copper oxide is:

The colour formed when the hydrogen gas is passed over heated copper oxide is reddish brown.
When the hydrogen gas is passed over the heated copper oxide in the reaction copper oxide loses oxygen and is reduced. The hydrogen is gaining oxygen and is being oxidised. The reddish brown colour is formed when the hydrogen gas is passed over heated copper oxide. So, Copper and water are formed in this reaction. 
$\mathit{CuO}\left(s\right)+H_2\left(g\right)\to \mathit{Cu}+H_{2}O$