Question

Will oxidation number increase or decrease in reduction reaction

Answer 1

When oxidation occurs, an element loses electrons and its oxidation number increases (becomes more positive). When reduction occurs, an element gains electrons and its oxidation number decreases or is reduced (becomes more negative).

Answer 2

Oxidation number decreases in a reduction reaction. This is because:

• Reduction refers to the loss of electrons.
• Hence, if a species reduces, it tends to lose electrons and decrease its oxidation number.
• For example, when Cu²⁺ reduces to form Cu, there is a decrease in the oxidation number of the copper atom from +2 to zero. Therefore, the oxidation number decreases in a reduction process.