Formic acid, also known as formic acid. Ant secretions and bee secretions contain formic acid, which was originally made by distilling ants, hence the name. Formic acid is colorless and pungent. It is also corrosive and causes blistering and swelling on contact with human skin. Because of the special structure of formic acid, one of its hydrogen atoms is directly connected to the carboxyl group. It can also be seen as a hydroxyformaldehyde. Thus formic acid has both acid and aldehyde properties. In the chemical industry, formic acid is used in rubber, medicine, dyes, leather industries.

Flammable. Can be miscible with water, ethanol, ether and glycerol, and most polar organic solvents miscible, also has a certain solubility in hydrocarbons.

The relative density (d204) is 1.220.

Heat of combustion 254.4kJ/mol,

The critical temperature is 306.8℃,

Critical pressure 8.63MPa.

Flash point 68.9℃ (open cup).

The density is 1.22,

Relative vapor density 1.59 (air =1),

Saturated vapor pressure (24℃) 5.33kPa.

High concentrations of formic acid tend to freeze in winter. Miscible with water, insoluble in hydrocarbons, but miscible in alcohol. In hydrocarbons and in the gaseous state, formic acid occurs as a dimer bonded by hydrogen bonds. In the gaseous state, hydrogen bonding results in a large deviation between the formic acid gas and the ideal gas equation of state. Liquid and solid formic acid consists of formic acid molecules that are continuously bonded by hydrogen bonds.