1. Mass and energy are separately conserved in a reaction. II. Law of conservation of mass and the law of conservation of energy are valid for every reaction. I and II both are correct lis correct and II is incorrect lis incorrect and II is correct I and II both are incorrect

I and II both are correct.<br /><br />The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction. Instead, the mass of the reactants is equal to the mass of the products. This means that the total mass of the substances involved in a reaction remains constant, even though the individual masses of the reactants and products may change.<br /><br />The law of conservation of energy states that energy cannot be created or destroyed, only transformed from one form to another. In a chemical reaction, the total energy of the system and its surroundings remains constant, even though the individual energies of the reactants and products may change.<br /><br />Both of these laws are valid for every chemical reaction, and they are fundamental principles of chemistry.