Consider the reaction that occurs when copper is added to nitric acid. Upper C u (s) plus 4 upper H upper N upper O subscript 3 (a q) right arrow upper C u (upper N upper O subscript 3) subscript 2 (a q) plus 2 upper N upper O 2 (g) plus 2 upper H 2 upper o (l). What is the reducing agent in this reaction?

Cu

Explanation:

In the given reaction of the addition of copper to nitric acid,

Cu(s) + 4HNO3(aq) -> Cu(NO3)2(aq) + 2NO2(g) + 2H2O(l)

Cu or copper would be characterized as the reducing agent in this reaction. It is the chemical substance that is losing electrons and being oxidized due to this reduction/loss in this redox reaction as it is the metal that loses electrons by reacting with the non-metals.