Question

---------- is used as a reducing agent in metallmgical process. ​

Answer 1

Answer:

carbon monoxide

…also useful as a metallurgical reducing agent, because at high temperatures it reduces many metal oxides to the elemental metal. For example, copper(II) oxide, CuO, and iron(III) oxide, Fe2O3, are both reduced to the metal by carbon monoxide.

Answer 2

K, CA, Na are some examples