This series of chemical reactions represents the conversion of ethene $C2H4$ to ethanol $C2H5OH$ to acetic acid $CH3COOH$ to carbon dioxide $CO2$. The overall reaction can be described as:

C2H4 --> C2H5OH --> CH3COOH --> CO2 $+CO2$

Each arrow indicates a separate step in the reaction pathway, with the final step involving the combustion of acetic acid to produce carbon dioxide.