Electrifying the Future: Ace Your 3rd Year Electrical TQ Exam 2026!

When a fuel burns in air, its hydrogen and carbon react with oxygen to form oxidation products. Water (H2O) is always produced from hydrogen, and carbon dioxide (CO2) is the usual product from carbon in complete combustion. If oxygen is limited, carbon monoxide (CO) can form as an incomplete combustion product. Nitrogen from the air generally stays as N2 or forms NOx only under certain conditions, so it isn’t a typical primary product of combustion.

Therefore, the set that lists water and carbon monoxide best reflects combustion products you’d see under varying oxygen conditions. The other options include elements (H or N) or reactants (N2 and O2) rather than typical combustion products.