Answer : The balanced chemical reaction will be,
[tex]2C_7H_{14}+21O_2\rightarrow 14CO_2+14H_2O[/tex]
Explanation :
Balanced chemical reaction : It is defined as the reaction in which the number of atoms of individual elements present on reactant side must be equal to the product side.
Combustion reaction : It is a chemical reaction in which a hydrocarbon reaction with the oxygen to give product as carbon dioxide and water.
The unbalanced chemical reaction is,
[tex]C_7H_{14}+O_2\rightarrow CO_2+H_2O[/tex]
This reaction is an unbalanced chemical reaction because in this reaction number of carbon , hydrogen and oxygen atoms are not balanced.
In order to balance the chemical equation, the coefficient '2' put before the [tex]C_7H_{14}[/tex], the coefficient '21' put before the [tex]O_2[/tex], the coefficient '14' put before the [tex]CO_2[/tex] and the coefficient '14' put before the [tex]H_2O[/tex] then we get the balanced chemical equation.
The balanced chemical reaction will be,
[tex]2C_7H_{14}+21O_2\rightarrow 14CO_2+14H_2O[/tex]