Question

what is the chemical composition of formalin?​

Answer 1

CH2O

Formalin: A 37% aqueous (water) solution of formaldehyde, a pungent gas, with the chemical formula HCHO, used as an antiseptic, disinfectant, and especially today as a fixative for histology (the study of tissues under the microscope).

Answer 2

Explanation:

As stated by others formalin is a 38–40% solution of formaldehyde in water. Formaldehyde is a gas with the structure, H2C=O. In water, its a different story. Formaldehyde primarily forms a water soluble “hydrate” in water, H2C(OH)2, and oligomeric forms, i.e. general formula: HOCH2–(OCH2)nOH. The amount of these oligomers (usually only a few %) depends upon conc. and the presence of alcohols, added to keep this oligomerisation to a minimum.