Upon oxidizing formaldehyde, which compound is produced?

When formaldehyde undergoes oxidation, the primary product that is formed is formic acid. The oxidation of formaldehyde involves the addition of an oxygen atom to the molecule, which transforms it into an acid. This process follows the general chemical principles where aldehydes can be oxidized to carboxylic acids.

Formaldehyde, being the simplest aldehyde, has the formula HCHO. Upon the introduction of an oxidizing agent and the conditions for oxidation, the hydrogen atom in the aldehyde group (–CHO) is replaced with an oxygen atom, leading to the formation of formic acid (HCOOH), which retains the carbon skeleton while introducing the carboxylic acid functional group.

The other compounds listed do not directly result from the oxidation of formaldehyde. Acetaldehyde is an aldehyde that can be produced from ethanol; methanol is a simple alcohol and not produced from the oxidation of formaldehyde; and ethylene glycol is a diol, not a product of this oxidation process. Thus, formic acid is the correct answer due to the straightforward oxidation pathway of formaldehyde.