6.3 Why is the extraction of copper from pyrites more difficult than that from its oxide ore through reduction?

The Gibbs free energy of formation (∆fG) of $C{u}_{2}S$ is less than that of .

Therefore, ${H}_{2}$ and C cannot reduce $C{u}_{2}S$ to Cu.

On the other hand, the Gibbs free energy of formation of $C{u}_{2}S$ is greater than that of CO. Hence, C can reduce $C{u}_{2}S$  to Cu.

Hence, the extraction of copper from its pyrite ore is difficult than from its oxide ore through reduction.