The use of formalin solution as an end-point indicator in the titratio
n of both acids and bases in aqueous solutions was investigated. In bo
th instances, a lowering in temperature at the end-point, due to depol
ymerization of poly(oxymethylene glycols), was observed. Endothermic e
nd-points were also obtained by using paraformaldehyde as an end-point
indicator in titrations of acids in aqueous solutions. The use of par
aformaldehyde in the titration of very weak acids and of some sparingl
y soluble acids solubilized in micellar suspensions of cationic deterg
ents was also investigated.