Question

In the chemical reaction:
${{K}_{2}}C{{r}_{2}}{{O}_{7}}+x{{H}_{2}}S{{O}_{4}}+yS{{O}_{2}}\to {{K}_{2}}S{{O}_{4}}+C{{r}_{2}}{{(S{{O}_{4}})}_{3}}+z{{H}_{2}}O$ x, y, z are respectively:
a.) 1, 3, 1
b.) 4, 1, 4
c.) 3, 2, 3
d.) 2, 1, 2

Answer 1

To find the value of x, y and z we have to balance the chemical reaction and to balance a chemical reaction we should write all the products and bi products which are formed after the reaction.

Complete Solution :
- We have to check whether the reaction is balanced or not. Law of conservation of mass states that both the reactants and products have the same mass. And we know that in a chemical reaction mass can neither be created nor be destroyed. Initially we will check whether the given reactants and products are correct or not. There are coefficients which are used to balance the reaction. We should remember that the subscript near each element cannot be changed, we can only change the coefficients to balance the reaction.
- The number of sulphur atoms on the reactant side is equal to the number of sulphur atoms present on the product side i.e. $x + y = 4--(1)$
The number of hydrogen atoms on the reactant side is equal to the number of hydrogen atoms present on the product side i.e. $2x = 2z--(2)$
The number of oxygen atoms on the reactant side is equal to the number of oxygen atoms present on the product side i.e. $4x + 7 + 2y = 4 + 12 + z--(3)$
After solving the three equations we get:
X = 1, y = 3 and z = 1.
So, the correct answer is “Option A”.

Note: Balancing a chemical equation means that we add stoichiometric coefficient to the products and to the reactants. The balancing of a chemical reaction is important because any chemical equation must follow the law of constant proportion and the law of the conservation of mass which means that there should be the same number of atoms in both the reactants as well as the product side.