Boric Acid

Boric Acid is a weak, monobasic Lewis acid of boron, often used as an antiseptic, insecticide, flame retardant, neutron absorber, or precursor to other chemical compounds. It has the chemical formula H3BO3 (sometimes written B(OH)3), and exists in the form of colorless crystals or a white powder that dissolves in water.

Chemical Properties

Boric acid is a weak acid, with a pKa (acid dissociation constant) of 9.24 (at 25 °C). It is soluble in boiling water. When heated above 170 °C, it dehydrates, forming metaboric acid (HBO2). Further heating leads to boron trioxide.

Uses

Boric acid has a variety of applications. It is a common ingredient in household products such as laundry boosters, tooth bleaching powders, and roach poisons. In industrial settings, it is used as a buffering agent, a flame retardant, and a corrosion inhibitor. In medicine, it is used as an antiseptic for minor burns or cuts and is sometimes used in dressings or salves or is applied in a very dilute solution as an eye wash.

Health Effects

Exposure to boric acid can be harmful. Symptoms of acute exposure include redness, pain, or blurred vision if exposed to the eyes; dryness, nosebleeds, cough, shortness of breath, or sore throat if exposed to the respiratory system; and skin redness or a rash if exposed to the skin. Chronic exposure to boric acid by mouth can lead to damage to the nervous system and can cause convulsions and skin rash.

Safety

Boric acid is not highly toxic, but it is a potential irritant to the skin and eyes. It should be kept out of reach of children and pets. If ingested, medical attention should be sought immediately.

See Also

• Boron
• Acid
• Antiseptic
• Insecticide
• Flame retardant
• Neutron absorber