Question

How do you balance the following chemical equations by adding coefficients?
$HCl + NaOH \to {H_2}O + NaCl$
$F{e_2}{O_3} + C \to Fe + C{O_2}$
$S{O_2} + {O_2} \to S{O_3}$

Answer 1

The balanced chemical equation is a symbolic representation of chemical reaction where the number of atoms on the left side of the equation (reactant side) and right side of the equation (product side) are equal.

Complete step by step answer:
The chemical equation is the symbolic representation of the chemical reaction where the atom or compounds are represented by the help of their symbol or formulae.
The balanced chemical equation is defined as the balanced form of chemical equation where the number of atoms on the reactant side is equal to the number of atoms on the product side.
Reaction 1:
$HCl + NaOH \to {H_2}O + NaCl$
In this reaction hydrochloric acid reacts with sodium hydroxide to form water and sodium chloride.

Name of atom	Number in reactant side	Number in product side
O	1	1
H	2	2
Cl	1	1
Na	1	1

The given equation is already balanced.
Reaction 2:
$F{e_2}{O_3} + C \to Fe + C{O_2}$
In this reaction, iron (III) oxide reacts with carbon to form iron and carbon dioxide.

Name of atom	Number in reactant side	Number in product side
Fe	2	1
O	3	2
C	1	1

To balance the equation, multiply the iron(II) oxide with coefficient 2, carbon with coefficient 3 on the reactant side and multiply iron with 4, carbon dioxide with 3 on the product side.
The balanced equation is shown below.
$2F{e_2}{O_3} + 3C \to 4Fe + 3C{O_2}$

Name of atom	Number in reactant side	Number in product side
Fe	4	4
O	6	6
C	3	3

Reaction 3:
$S{O_2} + {O_2} \to S{O_3}$
In this reaction sulfur dioxide reacts with oxygen to form sulfur trioxide.

Name of atom	Number in reactant side	Number in product side
S	1	1
O	4	3

To balance the equation, multiply the sulfur dioxide with 2 in the reactant side and 2 with sulfur trioxide on the product side.The balanced equation is shown below.
$2S{O_2} + {O_2} \to 2S{O_3}$

Name of atom	Number in reactant side	Number in product side
S	2	2
O	6	6

Note:
While balancing the equation, such coefficients are used so that the number of atoms on both sides of the equation become equal. The balanced chemical equation follows Law of conservation of mass.