Formalin is a 37% aqueous solution of formaldehyde (HCHO) , an aldehyde,which is widely used as disinfectant and preservative for biological specimens like cadavers ,preserved for study and research purposes. It is also used as a fixative for histological specimens (tissue segment which is observed and studied under a microscope) .
Final Answer:
Thus, it can be concluded that formalin is basically a solution comprising around 37% HCHO and 63% H2O.
