# Incomplete combustion

I cannot find a definitive equation that describes the incomplete combustion of a hydrocarbon. Equations $1$, $2$ and $3$ are some of the variations I have found.

Is it,

$(1)$ $\ce{C_xH_y + O_2 \rightarrow CO + H_2O}$,

$(2)$ $\ce{C_xH_y + O_2 \rightarrow CO2 + CO + H_2O}$ or,

$(2)$ $\ce{C_xH_y + O_2 \rightarrow CO2 + CO + C + H_2O}$?