Question

What is the complete combustion of propanol $\left( {{\text{C}}_{3}}{{\text{H}}_{7}}\text{OH} \right)$ with oxygen?

Answer 1

Hint: The reaction of alcohols with oxygen is similar to the combustion reaction of hydrocarbons with oxygen where carbon dioxide and water are produced as the reaction product.

Complete answer:
A combustion reaction is a reaction in which a fuel or a substance reacts with oxygen gas and releases energy in the form of heat and light. Complete combustion of hydrocarbons takes place in a sufficient amount of oxygen.
On complete combustion, almost all hydrocarbons burn with a blue flame. But as the size of hydrocarbons increases, the combustion reaction tends to be less complete and we are more likely to get a yellow smoky flame.
The complete combustion of propanol is a highly exothermic process. The reaction involved can be written as:
\[{{\text{C}}_{\text{3}}}{{\text{H}}_{\text{7}}}\text{OH (g)}+{{\text{O}}_{\text{2}}}\text{ (g)}\to \text{C}{{\text{O}}_{\text{2}}}\text{ (g)}+{{\text{H}}_{\text{2}}}\text{O (g)}\]
This is not a balanced equation. For balancing it, we first need to balance the number of carbon, hydrogen, and oxygen atoms.
\[{{\text{C}}_{\text{3}}}{{\text{H}}_{\text{7}}}\text{OH (g)}+\dfrac{9}{2}{{\text{O}}_{\text{2}}}\text{ (g)}\to 3\text{C}{{\text{O}}_{\text{2}}}\text{ (g)}+4{{\text{H}}_{\text{2}}}\text{O (g)}\]
Now, After this we can rewrite this equation as follows:
\[\text{2}{{\text{C}}_{\text{3}}}{{\text{H}}_{\text{7}}}\text{OH (g)}+9{{\text{O}}_{\text{2}}}\text{ (g)}\to 6\text{C}{{\text{O}}_{\text{2}}}\text{ (g)}+8{{\text{H}}_{\text{2}}}\text{O (g)}\]
Hence, this is the complete combustion of propanol $\left( {{\text{C}}_{3}}{{\text{H}}_{7}}\text{OH} \right)$ with oxygen.

Additional information:
The larger hydrocarbons are difficult to ignite because the bigger molecules do not vaporize easily due to greater Van der Waals attractions between molecules which make them difficult to break away from each other to turn to gas.

Note:
The difference between complete and incomplete combustion is that incomplete combustion takes place where there is not enough oxygen present to react with all of the hydrocarbons and it results in the formation of carbon or carbon monoxide which is a colorless poisonous gas.