xidation in redox reactions involves a. a loss of electrons and an increase in the oxidation number b. a gain of electrons and an increase in the oxidation number c. a loss of electrons and a reduction in the oxidation number d. a gain of electrons and a decrease in the oxidation number

Option a is the right one

Explanation:

Redox reactions are defined as the reactions where one element is oxidized (so the oxidation state is increased); and another element is reduced (oxidation state decreases). These changes in the oxidations states are defined by a transference of electrons.

When the oxidation state decrease → reduction → the element gains electrons

When the oxidation state increase → oxidation → the element release electrons