Question

Balance the following equation:
$${\text{Fe}}{{\text{C}}_{\text{2}}}{{\text{O}}_{\text{4}}}{\text{ + KMn}}{{\text{O}}_{\text{4}}}{\text{ + }}{{\text{H}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{4}}} \to {\text{F}}{{\text{e}}_{\text{2}}}{{\text{(S}}{{\text{O}}_{\text{4}}}{\text{)}}_{\text{2}}}{\text{ + C}}{{\text{O}}_{\text{2}}}{\text{ + MnS}}{{\text{O}}_{\text{4}}}{\text{ + }}{{\text{K}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{4}}}{\text{ + }}{{\text{H}}_{\text{2}}}{\text{O}}$$
A. $${\text{10Fe}}{{\text{C}}_{\text{2}}}{{\text{O}}_{\text{4}}}{\text{ + 6KMn}}{{\text{O}}_{\text{4}}}{\text{ + 24}}{{\text{H}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{4}}} \to {\text{5F}}{{\text{e}}_{\text{2}}}{{\text{(S}}{{\text{O}}_{\text{4}}}{\text{)}}_{\text{2}}}{\text{ + 20C}}{{\text{O}}_{\text{2}}}{\text{ + 6MnS}}{{\text{O}}_{\text{4}}}{\text{ + 3}}{{\text{K}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{4}}}{\text{ + 24}}{{\text{H}}_{\text{2}}}{\text{O}}$$
B. $${\text{5Fe}}{{\text{C}}_{\text{2}}}{{\text{O}}_{\text{4}}}{\text{ + 4KMn}}{{\text{O}}_{\text{4}}}{\text{ + 12}}{{\text{H}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{4}}} \to 7{\text{F}}{{\text{e}}_{\text{2}}}{{\text{(S}}{{\text{O}}_{\text{4}}}{\text{)}}_{\text{2}}}{\text{ + 20C}}{{\text{O}}_{\text{2}}}{\text{ + 6MnS}}{{\text{O}}_{\text{4}}}{\text{ + 3}}{{\text{K}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{4}}}{\text{ + 24}}{{\text{H}}_{\text{2}}}{\text{O}}$$
C. $${\text{10Fe}}{{\text{C}}_{\text{2}}}{{\text{O}}_{\text{4}}}{\text{ + 4KMn}}{{\text{O}}_{\text{4}}}{\text{ + 24}}{{\text{H}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{4}}} \to 6{\text{F}}{{\text{e}}_{\text{2}}}{{\text{(S}}{{\text{O}}_{\text{4}}}{\text{)}}_{\text{2}}}{\text{ + 20C}}{{\text{O}}_{\text{2}}}{\text{ + 6MnS}}{{\text{O}}_{\text{4}}}{\text{ + 3}}{{\text{K}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{4}}}{\text{ + 24}}{{\text{H}}_{\text{2}}}{\text{O}}$$
D. None of these

Answer 1

Hint: The chemical equation is said to be balanced if the number of atoms of the species that are involved in the chemical is the same on both the sides that are the reactants and the products. We use the chemical equations to represent the chemical reaction with help of the chemical formulas of the species involved in the reaction. The mass should remain the same on both reactants and products side because the mass cannot be created and not be destroyed.

Complete step by step answer:
So let us first balance the equations by first calculating the number of atoms that are present in the reaction.
So let us see the below equation for balancing the reaction:
$${\text{Fe}}{{\text{C}}_{\text{2}}}{{\text{O}}_{\text{4}}}{\text{ + KMn}}{{\text{O}}_{\text{4}}}{\text{ + }}{{\text{H}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{4}}} \to {\text{F}}{{\text{e}}_{\text{2}}}{{\text{(S}}{{\text{O}}_{\text{4}}}{\text{)}}_{\text{2}}}{\text{ + C}}{{\text{O}}_{\text{2}}}{\text{ + MnS}}{{\text{O}}_{\text{4}}}{\text{ + }}{{\text{K}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{4}}}{\text{ + }}{{\text{H}}_{\text{2}}}{\text{O}}$$
So the number of Fe atoms in the reactants side is 1, for carbon it is 2, for oxygen it is 12 , for potassium it is 1 , for Mn it is 1 , for hydrogen it is 2 and for S it is 1. Whereas the number of each species atom in products side for Fe is 2, for carbon it is 1, for oxygen it is 23, for potassium it is 2, for Mn it is 1, for hydrogen it is 2 and for S it is 5.
So now to balance the sulphur atoms we need to multiply sulphuric acid by 5 to get the same number of sulphur on both sides. Then to balance hydrogen atoms we need to multiply water by 5 on the product side so that we have the same number of hydrogen on both sides.
To balance the potassium atoms we need to multiply the potassium manganate by 2 in the reactant side so both sides have the same number of potassium atoms.
To balance the manganese atoms we need to multiply $${\text{MnS}}{{\text{O}}_{\text{4}}}$$on the product side by two so that the manganese atom is balanced. Now to balance iron atoms we need to multiply $${\text{Fe}}{{\text{C}}_{\text{2}}}{{\text{O}}_{\text{4}}}$$by two. Now we again need to balance sulphur atoms as they are six on product side and five at reactant so we will add one more molecule of sulphuric acid on reactant side. Now to balance hydrogen we need to add one more molecule of water on the product side. Now to balance carbon again we need to add 4 molecules of carbon dioxide on the product side. So too balance oxygen we need to add 8 molecules of $${\text{Fe}}{{\text{C}}_{\text{2}}}{{\text{O}}_{\text{4}}}$$ and 4 molecules of potassium manganese and 18 molecules of sulphuric acid and 5 molecules of iron sulphate and 16 molecules of carbon dioxide and 4 molecules of manganese sulphate and 3 molecules of potassium sulphate and 18 molecules of water. So the equation which we get is $${\text{10Fe}}{{\text{C}}_{\text{2}}}{{\text{O}}_{\text{4}}}{\text{ + 6KMn}}{{\text{O}}_{\text{4}}}{\text{ + 24}}{{\text{H}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{4}}} \to {\text{5F}}{{\text{e}}_{\text{2}}}{{\text{(S}}{{\text{O}}_{\text{4}}}{\text{)}}_{\text{2}}}{\text{ + 20C}}{{\text{O}}_{\text{2}}}{\text{ + 6MnS}}{{\text{O}}_{\text{4}}}{\text{ + 3}}{{\text{K}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{4}}}{\text{ + 24}}{{\text{H}}_{\text{2}}}{\text{O}}$$

So, the correct answer is Option A.

Note: The skeletal chemical equation does not tend to follow the law related to conservation of mass. The law of conservation of mass is followed in stoichiometric relationships. One needs to be very careful balancing the equation and should calculate the number of atoms of each species again and again after adding molecules into it.