Question

Write the balanced chemical equation when barium reacts with hydrochloric acid.
(A) \[{\text{Ba + 2HCl}} \to {\text{BaC}}{{\text{l}}_{\text{2}}}{\text{ + 2H}}\]
(B) \[{\text{Ba + 2HCl}} \to {\text{BaC}}{{\text{l}}_{\text{2}}}{\text{ + }}{{\text{H}}_{\text{2}}}\]
(C) \[{\text{Ba + 2HCl}} \to {\text{Ba}}{{\text{H}}_{\text{2}}}{\text{ + Cl}}\]
(D) \[{\text{Ba + HCl}} \to {\text{BaHCl}}\]

Answer 1

Hint: A balanced chemical equation follows the law of conservation of mass. Thus, we need to make the ratio of the number of reactants and the number of products the same. The reaction of barium with hydrochloric acid liberates hydrogen gas and yields barium chloride as the product.

Complete step by step answer: When barium reacts with hydrochloric acid, barium chloride is obtained with liberation of hydrogen gas.
First for the given reaction, let's write the word equation.
\[{\text{Barium + Hydrochloric acid}} \to {\text{Barium chloride + Hydrogen}}\]
Now, we need to write the chemical formula for each compound and substitute in the word equation.
\[{\text{Ba + HCl}} \to {\text{BaC}}{{\text{l}}_{\text{2}}}{\text{ + }}{{\text{H}}_{\text{2}}}\]
Finally, we need to balance the above chemical equation.
While balancing a chemical equation, we need to determine the ratio of reactants to products which allows for the total number of atoms of reactants to match the number of atoms of the products.
 Since the type of atoms does not change and the number of atoms stays that same, the total mass that goes into the chemical change will match the mass that comes out after the change. So, the law of conservation of mass is the principle behind balancing a chemical equation.
\[{\text{Ba + 2HCl}} \to {\text{BaC}}{{\text{l}}_{\text{2}}}{\text{ + }}{{\text{H}}_{\text{2}}}\]

So, the correct option is B.

Note: A chemical equation which does not follow the law of conservation of mass is called skeleton equation. Any chemical equation must be balanced and obey the law of conservation of mass. Liberation of hydrogen gas is the crucial side product when barium reacts with hydrochloric acid.