Q. What type of chemical reaction is C6H12O6 6O2 → 6CO2 6H2O

The reaction C6H12O6 + 6O2 → 6CO2 + 6H2O represents cellular respiration, which is classified as a combustion reaction and, more specifically, a complete oxidation reaction. In this process, glucose (a simple sugar) reacts with oxygen to produce carbon dioxide, water, and energy in the form of ATP. From a chemical classification standpoint, this is an exothermic redox reaction where glucose is oxidized (loses electrons) and oxygen is reduced (gains electrons), breaking high-energy C-H and C-C bonds and forming lower-energy C=O and H-O bonds.

This equation describes one of the most fundamental energy-producing processes in living organisms, from bacteria to humans. While we commonly call it cellular respiration when it occurs in cells through a complex series of enzyme-controlled steps, the overall chemical transformation mirrors the combustion of glucose if you were to simply burn sugar in air. The reaction releases approximately 686 kilocalories per mole of glucose, which cells capture gradually through glycolysis, the Krebs cycle, and the electron transport chain rather than all at once as heat. Understanding this reaction as both a combustion and a redox process helps explain why we need to breathe oxygen and why we exhale carbon dioxide—we're essentially "burning" our food at a controlled rate to power our bodies.