ANS:B - carbon monoxide

The main reducing agent in an iron blast furnace is carbon monoxide. In the iron blast furnace, iron ore (mainly Fe2O3) is reduced to iron metal (Fe) using carbon monoxide (CO) as the primary reducing agent. This process occurs in the lower part of the blast furnace, where temperatures can reach over 1500°C. The overall reaction involves the reduction of iron(III) oxide (Fe2O3) by carbon monoxide (CO) to produce iron (Fe) and carbon dioxide (CO2): Fe2O3+3CO→2Fe+3CO2Fe2​O3​+3CO→2Fe+3CO2​ Carbon monoxide is produced by the combustion of coke (carbon) in the presence of hot air blown into the furnace. The carbon monoxide then reacts with the iron ore to reduce it to metallic iron. Therefore, carbon monoxide is the main reducing agent responsible for extracting iron from its ores in the blast furnace process.