Theoretically, the complete reduction of formaldehyde would produce which gas?

The complete reduction of formaldehyde theoretically results in the production of methane. Formaldehyde, with the chemical formula CH2O, consists of one carbon atom, two hydrogen atoms, and one oxygen atom. When it undergoes reduction, which is the gain of electrons and often involves the addition of hydrogen or the removal of oxygen, it can be transformed into simpler hydrocarbons.

In the case of formaldehyde, if it undergoes complete reduction, it loses the oxygen and combines with more hydrogen, ultimately leading to the formation of methane (CH4), which is a stable, simple alkane. Methane is composed of one carbon atom bonded to four hydrogen atoms, fitting the outcome of fully reducing the single carbon compound that is formaldehyde.

The other options, such as ethanol, propane, and butane, represent different molecular structures and compositions that are not the direct result of reducing formaldehyde. Ethanol contains two carbon atoms and does not match the complete reduction outcomes expected from formaldehyde. Propane and butane consist of three and four carbon atoms, respectively, which also diverge significantly from the structure of formaldehyde and the resulting product after reduction. Therefore, methane emerges as the most logical and chemically consistent outcome when