ALDEHYDES
When alcohols are treated with certain oxidizing agents two hydrogen atoms are removed from each molecule of the alcohol. The resulting compounds are known as aldehydes. The relation of the aldehydes derived from methyl and ethyl alcohol to the alcohols themselves may be shown as follows:
| Alcohols | {CH3OH | Corresponding aldehydes | {CH2O |
| {C2H5OH | {C2H4O |
The first of these (CH2O) is a gas known as formaldehyde. Its aqueous solution is largely used as an antiseptic and disinfectant under the name of formalin. Acetaldehyde (C2H4O) is a liquid boiling at 21°.