Answer the following case-based question given below:
The metals in the middle of the activity series such as iron, zinc, lead, copper, etc., are moderately reactive. These are usually present as sulphides or carbonates in nature. It is easier to obtain a metal from its oxide, as compared to its sulphides and carbonates. Therefore, prior to reduction, the metal sulphides and carbonates must be converted into metal oxides.
a. What is calcination?
b. Give a suitable example for the process roasting.
c. Name any two reducing agent which can be used to extract metal from metal oxide.
d. When manganese dioxide reacts with aluminium powder, the reaction produces: