Question

Assertion: The balancing of chemical equations is based on the law of conservation of mass.
Reason: Total mass of reactants is equal to total mass of products.
A) Both assertion and reason is correct and reason is the correct explanation of assertion B) Both assertion and reason is correct but reason is not the correct explanation of assertion C) Assertion is correct but reason is incorrect D) Assertion is incorrect but reason is correct

Answer 1

Hint: The law of conservation of mass states that mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations.According to the law of conservation of mass, the mass of the products in a chemical reaction must equal the mass of the reactants.

Complete step- by- step answer:
- The law of conservation of mass states that mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations.
- According to the law of conservation of mass, the mass of the products in a chemical reaction must equal the mass of the reactants.
- This law is called the law of indestructibility of matter. We take the example of formation of a water molecule.
- When we add one atom of oxygen with mass 16 and two atoms hydrogen of total mass 2, we get one water molecule with mass as18. Thus, it is verified that the mass is conserved or same in both sides of the reaction.
- Discussing option A, it says that both the assertion and reason are true and the reason is the correct explanation of the assertion. So, if we see that in any reaction the total mass created is the total mass lost in the same reaction.
Clearly, the answer is A.

Note: Further, this law is not at all valid for nuclear reactions and radioactive disintegrations. This is because during such reactions, a large amount of energy is released which results in a change in significant mass of reactants. Thus, the law of conservation of mass does not apply to such reactions.