What is the correct chemical equation for the fermentation of glucose to produce ethanol?

The fermentation of glucose to produce ethanol is most accurately represented by the equation where one molecule of glucose (C₆H₁₂O₆) is converted into two molecules of ethanol (C₂H₅OH) and two molecules of carbon dioxide (CO₂). This process occurs in the absence of oxygen, typically through the action of yeast, which breaks down the glucose through anaerobic respiration.

In the equation C₆H₁₂O₆ -> 2C₂H₅OH + 2CO₂, glucose is used as a substrate, and during fermentation, the energy stored in glucose is released, producing ethanol and carbon dioxide as by-products. This is a simplified representation of cellular respiration specific to yeast, showcasing the conversion of carbohydrates into alcohol, which is integral in the brewing and baking industries.

The other equations do not accurately represent the fermentation process. For example, one alters the reactants and products involved, while another suggests a reaction that would typically be part of a different metabolic pathway, such as those involving the addition of water or oxygen, which is not characteristic of fermentation. Understanding the specific products and conditions of fermentation is crucial in grasping the fundamental principles of this biochemical reaction.