The chemical reaction in which both oxidation and reduction takes place is said to be redox reaction. In redox reaction, oxidation states of the elements in compounds changes as they are getting oxidised and reduced.
In redox reaction, there is no effect on the mass and charge of the compound. In beginning and after completion of the reaction, the total mass and total charge will remain same.
Thus, the total mass and total charge at the beginning of a redox reaction, the total mass and total charge upon completion of the reaction is same.
Option (4) is the correct answer.
