Which of the following is an essential condition for a redox reaction?

a. the reactants should be two elements.
b. the reactants should be two compounds.
c. the oxidation state of all the atoms should change.
d. the oxidation state of at least two atoms should change.

Answer;

C.The oxidation state of all the atoms should change.

Explanation;A redox reaction which is oxidation-reduction reaction is a type of chemical reaction that involves a transfer of electrons between two species. An oxidation-reduction reaction is any chemical reaction in which the oxidation number of a molecule, atom, or ion changes by gaining or losing an electron. In a redox reaction, the total number of electrons lost by the reducing agent must be equal to the number of electrons gained by the oxidizing agent.

Ithink about 50 % of an original isotope's number of atoms remain