Which of the following is the formula for acetic acid?

Acetic acid is a simple carboxylic acid with the molecular formula CH3COOH. This formula indicates that acetic acid consists of two carbon atoms (C), four hydrogen atoms (H), and two oxygen atoms (O). The structure of acetic acid features a methyl group (CH3-) attached to a carboxyl group (-COOH).

Understanding acetic acid's structure is important because it highlights the functional groups present. The carboxyl group is responsible for the acidic properties of acetic acid, which is why it is often used in various applications, including food preservation and chemical manufacturing.

In contrast, the other options provided correspond to different chemical compounds. For instance, ethyl alcohol (C2H5OH) is an alcohol and does not have the acidic properties associated with carboxylic acids. HNO3 is nitric acid, a strong inorganic acid, and H2SO4 is sulfuric acid, another strong inorganic acid. Neither of these compounds has the same structure or properties characteristic of acetic acid. Therefore, the identification of CH3COOH as the formula for acetic acid is accurate, given the chemical composition and structural features of the compound.