What chemical formula represents water?

The chemical formula that represents water is H2O. This formula is composed of two hydrogen atoms covalently bonded to one oxygen atom. Water is essential for all known forms of life and plays a critical role in many biological processes, including metabolism, temperature regulation, and the transportation of nutrients and waste within organisms.

In contrast, the other options represent different chemical compounds. CO2, for instance, is carbon dioxide, which is a gas produced by respiration in animals and used by plants during photosynthesis. NaCl is table salt, consisting of sodium and chloride ions, essential for maintaining electrolyte balance in the body. C2H5OH, known as ethanol, is an alcohol commonly found in beverages and used in various industrial applications. Each of these compounds has distinct properties and functions that differentiate them from water.