So if you decide to use either of them internally it’s good to know the reasons why Boric acid is a better choice.
HOW THEY ARE MADE?
Borax is mined out of the ground while boric acid is made from borax by reacting borax with hydrochloric acid. Borax is dissolved in boiling water, aqueous solution of hydrochloric acid is added, and when the solution cools, boric acid gets crystallised and is filtered out.
BORIC ACID CONTAINS MORE BORON
Boric acid contains 17.50% and Borax 11.30% of Boron. Moreover, borax retains much more water which increase its bulk. Therefore the molecular weight of Borax is a whopping 380 while the molecular weight of Boric acid is only 62.
BORAX CAN BE TOXIC AND CORROSIVE TO EYES
The National Pesticide Information Centre (NPIC) warns that when borax powder gets into our eyes, “it can be toxic and corrosive.” So, please keep Borax away from your eyes.
BORAX CONTAINS SODIUM
Boric acid contains Boron, Oxygen and Hydrogen while Borax (also known as sodium borate, or sodium tetraborate) contains two Sodium (Na) molecules which we really don’t need as there is already too much sodium in our diet and sodium contributes to high blood pressure.
BORAX DRIES OUT
Since Borax contains 10 water molecules it slowly loses water and “dries out” becoming rock hard and very difficult to work with.