Question

what is a reducing agent? and why is coke considered a reducing agent?

Answer 1

Reducing Agents are those compounds which carry out reduction of other substance either by providing hydrogen, or by removing oxygen from the other substance or by gaining electrons.

Coke C when reacted with moderately reactive metal oxides at high temperature it forms CO₂ and free metal during the metallurgical process. In this way coke play the role of removal of oxygen from metal oxide and hence act as reducing agent. The chemical equation is as follows :
2ZnO + C $\stackrel{∆}{\to }$ 2Zn + CO₂