Question

A reaction occurs between potassium carbonate and hydrochloric acid producing potassium chloride, carbon dioxide and water. The correct set of coefficients, respectively for the balanced chemical reaction is
A. 1,1,1,1,1
B. 1,2,2,1,1
C. 3,6,6,3,4
D. 8,6,5,10,5
E. 5,10,10,5,5

Answer 1

Hint: An equation is said to be balanced if it has equal numbers of atoms present for each element involved in the reaction and product sides. It is confirmed by simply adding up the number of elements on the reactant side and product side, if both are equal then that element is balanced. We will do the same for the other entire elements in the reaction to check for balanced chemical reaction.

Complete Step by step answer: for balancing a chemical reaction, we firstly should know the chemical formula of each compound in that reaction. After that we need to write the chemical equation. So here in this question we have:
 Potassium carbonate having chemical formula ${K_2}C{O_3}$ when reacts with hydrochloric acid having chemical formula $HCl$ will give products namely potassium chloride having chemical formula $KCl$, water and carbon dioxide having chemical formula as ${H_2}O,C{O_2}$ respectively.
Now the simple unbalanced chemical equation will be ${K_2}C{O_3} + HCl \to KCl + {H_2}O + C{O_2}$
The next step is to calculate the number of each element and balance them one by one.
So first we have potassium- on the reactant side the number of potassium atoms are 2 but on the product side the number of potassium atoms is one. So we will multiply potassium chloride $KCl$ by 2. Now we have our chemical equation with balanced potassium atom as-
${K_2}C{O_3} + HCl \to 2KCl + {H_2}O + C{O_2}$
For chlorine atoms, we have one chlorine atom on the reactant side, but 2 chlorine atoms on the product side. To balance them we will multiply hydrogen chloride $HCl$ by 2. Now we have our chemical reaction with balanced potassium and chlorine atom as-
${K_2}C{O_3} + 2HCl \to 2KCl + {H_2}O + C{O_2}$
Now for hydrogen atoms, we have 2 hydrogen atoms on the reactant side and 2 on the product side, so hydrogen is balanced.
Next we will check for oxygen, 3 oxygen atoms on reactant side and 3 atoms on product side, so oxygen is also balanced.
Next we have carbon, 1 carbon on the left side and 1 on the right. So the carbon is also balanced.
Therefore the balanced chemical that we have is-

${K_2}C{O_3} + 2HCl \to 2KCl + {H_2}O + C{O_2}$

So the correct option will be B. 1,2,2,1,1.

Note: We actually want the reaction to accurately represent what happens when we observe the chemical reaction in the real world. A balanced chemical reaction obeys the law of conservation of mass that is mass can never be created nor be destroyed. So mass of reactants should be equal to mass of products. And also balanced equation lets up predict the amount of reactants needed and amount of product formed