Question

How do we represent the complete (and incomplete) combustion of benzene?

Answer 1

`C_6H_6(l) +6O_2(g)rarr 4CO_2(g) + CO(g) + C(s) +3H_2O(l)`

Explanation:

Complete combustion would be represented by the equation:

`C_6H_6(l) +15/2O_2(g)rarr 6CO_2(g)+ 3H_2O(l)`

However, when benzene burns, it usually burns with a sooty flame (which indicates elemental carbon), and also carbon monoxide gas can be detected, both of which indicate INCOMPLETE combustion.

In the first equation, I assumed that SOME of the benzene was incompletely combusted to give SOME carbon, and SOME carbon monoxide. Is it balanced?

Would the energy output of this reaction (which we could certainly estimate) be greater or less (or the same) as complete combustion? Why so?