Question

Write chemical equation of combustion reaction for Toluene.

Answer 1

Hint: Toluene, also known as methylbenzene. It is a clear, transparent and colorless liquid with a distinctive sweet smell. Its molecular formula is \[{{C}_{7}}{{H}_{8}}\], with a molecular weight of 92.14 g/mol. Toluene has a wide application in industries as a solvent.

Complete Step by step solution:

Toluene is an aromatic hydrocarbon, a mono-substituted benzene derivative. It consists of a methyl group (\[C{{H}_{3}}\]) attached to a phenyl group. This methyl group has more electron-releasing property than a hydrogen atom at the same position, which makes toluene more reactive than benzene towards electrophiles.
Hydrocarbons are molecules which consist of both hydrogen and carbon. Regardless of the type of hydrocarbon, combustion with oxygen produces three products, namely, carbon dioxide, water and heat, as shown by the general equation:
\[{{C}_{x}}{{H}_{y}}+\left( x+\dfrac{y}{4} \right)({{O}_{2}})\to x(C{{O}_{2}})+\dfrac{y}{2}({{H}_{2}}O)\]
where, x = number of carbon atoms in the hydrocarbon
y = number of hydrogen atoms in the hydrocarbon

Therefore, the chemical equation for combustion of toluene can be given as follows:
\[{{C}_{7}}{{H}_{8}}+9{{O}_{2}}\to 7C{{O}_{2}}+4{{H}_{2}}O\]

Note: It is interesting to note that, the energy which is required to break the bonds between the hydrocarbon molecules is significantly less than the energy released while the formation of bonds in the \[C{{O}_{2}}\] and \[{{H}_{2}}O\] molecules. Due to this reason, the process of combustion releases more amounts of thermal energy (heat).
Since, the ratio of hydrogen to carbon varies in every hydrocarbon, they produce different ratios of water to carbon dioxide.