Answer: some other substance must be reduced.
Explanation:
Oxidation-reduction reaction or redox reaction is defined as the reaction in which oxidation and reduction reactions occur simultaneously.
Oxidation reaction is defined as the reaction in which a substance looses its electrons. The oxidation state of the substance increases.
[tex]M\rightarrow M^{n+}+ne^-[/tex]
The substance which gets oxidized itself reduces others and thus is called as reducing agent.
Reduction reaction is defined as the reaction in which a substance gains electrons. The oxidation state of the substance gets reduced.
[tex]M^{n+}+ne^-\rightarrow M[/tex]
The substance which gets itself reduced , oxidise others and thus is called as oxidising agent.
