Write the incomplete combustion reactions for methane,heptane,and nonane.

Incomplete combustion of alkanes occurs in a limited supply of oxygen,producing carbon monoxide $(CO)$ and water $(H_{2}O)$.
For methane $(CH_{4})$:
$CH_{4} + \frac{3}{2} O_{2} \rightarrow CO + 2 H_{2}O$
For heptane $(C_{7}H_{16})$:
$C_{7}H_{16} + 4 O_{2} \rightarrow 7 CO + 8 H_{2}O$
For nonane $(C_{9}H_{20})$:
$C_{9}H_{20} + 5 O_{2} \rightarrow 9 CO + 10 H_{2}O$
General reaction for incomplete combustion of alkanes:
$C_{n}H_{2n+2} + \left(\frac{n+1}{2}\right) O_{2} \rightarrow nCO + (n+1) H_{2}O$