The process in which oxidation number decreases is?

CONCEPT:

Reduction and Oxidation Numbers

• In a chemical reaction, the oxidation number (or oxidation state) of an element indicates the degree of oxidation (loss of electrons) or reduction (gain of electrons).
• Oxidation refers to an increase in oxidation number, while reduction refers to a decrease in oxidation number.
• The process in which the oxidation number decreases is termed as "Reduction."

EXPLANATION:

• The question asks for the process in which the oxidation number decreases.
• Reduction is the process where a substance gains electrons, resulting in a decrease in its oxidation number.
• For example, in the reaction:

  Cu²⁺ + 2e^- → Cu

  • The oxidation number of copper decreases from +2 (in Cu²⁺) to 0 (in Cu), indicating that copper is reduced.
• On the other hand, oxidation is the process where the oxidation number increases due to the loss of electrons.

Therefore, the correct answer is Reduction.