Question

___ is a byproduct of coal used in the extraction of metals.

Answer 1

Coke is used for metal extraction. A metal below carbon in the reactivity series (zinc to silver) may be extracted by heating the metal ore with carbon. During the reaction, the metal in the ore is displaced from its non-metal anion because carbon is more reactive than the metal. Carbon is used because it is cheap and readily available (coke and charcoal are both carbon). This form of extraction is less expensive than electrolysis. The metal in the ore is said to be reduced by reaction with carbon.