Which one of the following oxides is reduced by water gas to obtain the metal during its extraction?

Explain the thermodynamics of the extraction of iron from its oxide.

The compound$(s)$ that is(are) removed as slag during the extraction of copper is:
$1. CaO$
$2. FeO$
$3. Al_{2}O_{3}$
$4. ZnO$
$5. NiO$
Choose the correct answer from the options given below.

Which of the following has the lowest percentage of carbon?

Heating a mixture of $Cu_2O$ and $Cu_2S$ will give:

In the metallurgy of copper,metallic copper is finally formed in the furnace by the reactions: