We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
Formalin, which is permanently non-acid and only slightly alkaline, close to pH9, may be prepared by the addition of borax till a good red colour is shown with phenolphthalein, or a slaty blue with thymol blue, when added to the diluted formalin.
Distillation of formalin from solid magnesium carbonate gives an acid product, which is at pH4·4.
Formalin neutralised with sodium hydroxide becomes acid on standing, the change being more rapid in sunlight than in the dark. A reaction of pH5·2 was reached in fifty-six days in light, the initial value being pH8·0. Commercial formalin, “ 40 per cent,” may be as acid as pH2·8.
Email your librarian or administrator to recommend adding this journal to your organisation's collection.
