Answer: a. oxidation
Explanation:
Oxidation reaction is defined as the reaction in which a substance looses its electrons. The oxidation state of the substance increases.
\(X\rightarrow X^{n+}+ne^-\)
Electrochemistry is the branch of science which deals with the interconversion of electrical and chemical changes in the systems.
Reduction reaction is defined as the reaction in which a substance gains electrons. The oxidation state of the substance gets reduced.
\(X^{n+}+ne^-\rightarrow X\)
Half reaction is a reaction of oxidation or reduction occurring in anodic half or cathodic half of the cell. It could be oxidation or reduction.
