The reaction of natural gas (primarily methane, CH4) with oxygen to produce carbon monoxide (CO) and water (H2O) is an incomplete combustion reaction. The balanced chemical equation is:

2 CH4 + 3 O2 → 2 CO + 4 H2O

Here's a breakdown:

* CH4: Methane (natural gas)

* O2: Oxygen

* CO: Carbon monoxide

* H2O: Water

Important Note: This reaction is dangerous because carbon monoxide is a colorless, odorless, and poisonous gas. Incomplete combustion occurs when there isn't enough oxygen present for the methane to burn completely, resulting in the formation of carbon monoxide.