Question

How would you find a balanced equation of acetylene gas ($C_2{H}_2$) undergoes combustion to form carbon dioxide and water vapour?

Answer 1

Hint:The combustion of a material is a process where the material or compound reacts with molecular oxygen present in the air in order to form its oxides.
Organic compounds, upon reaction with oxygen, usually form carbon dioxide and water.
The combustion of a material is a process where the material or compound reacts with molecular oxygen present in the air in order to form its oxides.
Organic compounds, upon reaction with oxygen, usually form carbon dioxide and water.

Complete answer:
In order to balance the chemical equation we must first write the skeletal equation taking place in the reaction. As it is well mentioned that the gas is undergoing combustion so we will add oxygen as a reactant along with acetylene. The reaction is as follows,
$$C_2{H}_2+O_2\to C{O}_2+H_{2}O$$
Now we will consider each of these formulas individually in order to equate the number of atoms on both the sides. At first acetylene, we will write the coefficient one as the number of carbon atoms is higher on the reactant side as it is, and the coefficient of the carbon dioxide as two, to balance the number of carbon atoms on both sides.
$$C_2{H}_2+O_2\to 2C{O}_2+H_{2}O$$
As we can see the number of hydrogen atoms is also balanced on both the sides. In case of oxygen atoms, we can see that the number is five on the product side but it is two on the reactant side. So we need to multiply all the coefficients with two except for the oxygen on the reactant side, in order to avoid fractions. We get,
$$2C_2{H}_2+O_2\to 4C{O}_2+2H_{2}O$$
Now we can see that the number of oxygen atoms is five on the product side and two on the reactant side, so we will add a coefficient $5$ on the reactant side. We get,
$$2C_2{H}_2+5O_2\to 4C{O}_2+2H_{2}O$$
Now, as we can see all the atoms on both the sides are balanced. Hence the equation is balanced.

Note:The balancing of a chemical reaction requires a stepwise analysis of the number of atoms of each element present in the reactant as well as product.
In order to do so, we add required coefficients on either side of the reaction, and check if it is balanced.