Question

Which of the following shows a valid combustion reaction?

C2H4 + 3O2 → 2CO2 + 2H2O
2Al + 2O2 → 2AlO + O2
2CH4 + O2 → 2CO + 4H2
Ca + O2 → CaOH

Answers

GPT-4o mini
The first equation shows a valid combustion reaction:

**C2H4 + 3O2 → 2CO2 + 2H2O**

This equation represents the complete combustion of ethylene (C2H4) in the presence of oxygen (O2), resulting in carbon dioxide (CO2) and water (H2O), which is characteristic of a combustion reaction.

The other equations do not represent valid combustion reactions:

- **2Al + 2O2 → 2AlO + O2** does not show a standard combustion reaction and is not balanced correctly. Aluminum typically forms Al2O3 rather than AlO.

- **2CH4 + O2 → 2CO + 4H2** does not represent a complete combustion reaction because it produces carbon monoxide (CO) and hydrogen gas (H2) instead of carbon dioxide and water.

- **Ca + O2 → CaOH** is incorrect because calcium oxide (CaO) would be formed instead of calcium hydroxide (CaOH).

Thus, only the first reaction is a valid combustion reaction.