Question

Barium chloride reacts with sodium sulphate to form Barium sulphate and sodium chloride. Then, according to the the law of conservation of mass
A . The total mass of reactants, barium chloride and sodium sulphate taken is greater than the total mass of products, barium sulphate, sodium chloride formed
B . The total mass of reactants, barium chloride and sodium sulphate taken is less than the total mass of products, barium sulphate, sodium chloride formed
C . The total mass of the reactants is equal to the total mass of products
D . None of the above

Answer 1

Hint: Before we answer this question, we need to make sure that the equation is mentioned in the question is clear to us. Once we know the appropriate reactant and the relevant results from the reaction, we will easily be able to relate to the options.

Complete step-by-step answer:
Here is a reaction which shows the reaction that is mentioned in the question.
$\text{BaC}{{\text{l}}_{\text{2}}}\text{ + N}{{\text{a}}_{\text{2}}}\text{S}{{\text{O}}_{\text{4}}}\text{ }\xrightarrow{{}}\text{ BaS}{{\text{O}}_{\text{4}}}\text{ + NaCl}$.
We know that the law of conservation of mass or the principle of mass conservation states that for any closed system to all transfers of matter and energy, the mass of the system must remain constant over time. If the system's mass cannot change so quantity can neither be added nor removed.
We can see from the equation that none of the quantities are added or removed from the reactants to the products. In the question Barium Chloride got changed to Barium Sulfate in the product. And Sodium Sulphate got changed to Sodium Chloride in the product. Therefore it is the chlorides and the sulphates, in case of both the reactants and products that are being concerned in the equation.
Therefore, there is no addition of any kind of masses from the external atmosphere. Thus, we can say that the law of conservation of mass is preserved.
Therefore, we can see that Barium Chloride reacts with Sodium Sulphate to form Barium Sulphate and Sodium Chloride, which according to the law of conservation of mass, proves that the total mass of the reactants is equal to the total mass of products.
Therefore, the correct option is Option C.

Note: We can also define the law of conservation of mass in a way that in an isolated system mass is neither created nor destroyed by chemical reactions or any kind of physical transformations.
The law of conservation of mass is very important to the study and production of chemical reaction. If scientists know the quantities and identities of reactants for a particular reaction, then they can predict the amount of products that will be made.