Answer:
M is reducing agent.
Step-by-step explanation:
The oxidation reduction reactions are called redox reaction. These reactions are take place by gaining or losing the electrons and oxidation state of elements are changed.
Oxidation:
Oxidation involve the removal of electrons and oxidation state of atom of an element is increased.
Reduction:
Reduction involve the gain of electron and oxidation number is decreased.
Oxidizing agents:
Oxidizing agents oxidize the other elements and itself gets reduced.
Reducing agents:
Reducing agents reduced the other element are it self gets oxidized.
Consider the following reactions:
M → M⁺ + e⁻
In this reaction the oxidation state of M is increased which means it is reducing agent. It gives the electron to the other to reduce that element and itself gets oxidized.