The correct subscript for the reaction would be two. Oxygen gas exists as a diatomic molecule in nature. Also, the subscript two would balance the reaction. In balancing reactions, it is important that the atoms on each side of the reaction is equal.
Explanation:
Green chemistry
It is the process of designing a chemical compound via reducing or eliminating the use or generation of the hazardous substances .
It is a eco - friendly method , which does not harm the nature .
Ecological footprints
It is the tool to measure the demand of humans on nature , the quantity of nature humans require to support economy .
It tracks the demand of the humans via ecological accounting system .
Density and mass increases
In this reaction, Copper is the element being oxidized because it is losing electrons. It starts with a neutral charge (0) and ends up with a 6+ charge. Because its charge is increasing, it is being oxidized (losing electrons).
