Properties of Boric Powder
Boric acid or Boric Powder, also known as hydrogen borate or orthoboric acid, chemical formula of H3BO3 is oxygen-containing white crystals of born found in minerals and volcanic water or the end product of hydrolysis of boron halides or hydrides. Boric powder commonly get by acidifying and heating borax solution in chemistry. The shining white polymeric crystals structure of boric acid contains B(OH)3 units linked with infinite hexagonal layers due to hydrogen bonding.
The water solution of the boric acid molecule shows weak acid properties (pH = 9.2) but it does not use as a hydrogen ion donor, acts as a Lewis acid that accepting electron pair from the hydroxyl ion.
The conductance of the aqueous solution of boric acid is very weak which is enhanced by the addition of alcohol like ethanol, mannitol, glycerol, etc. Therefore, the strength of this acid now increases, and possible to reiterate the base solution using phenolphthalein as an indicator. This reaction name as borax phenolphthalein test that uses for testing glycerol in learning chemistry or organic chemistry.
Preparation of H3BO3
Boric acid, commonly obtained by boiling borax with acids and then crystallizing. The acid was also produced during the hydrolysis reaction of boron halides.
Na2B4O7(OH)4 + 2HCl + 3H2O → 4H3BO3 + 2NaCl
BCl3 + 3H2O → H3BO3 + 3HCl
Properties of Boric Acid Solution
Dilute aqueous boric acid solution contains mononuclear compound but various polymeric ions formed in concentrated chemical solution depending on the pH scale, concentration, and temperature. At 100°C, the acid changed to metaboric acid (HBO2), at 140°C to pyroboric acid, and finally at the higher temperature to B2O3. H3BO3 reacts with ethyl alcohol or ethanol in the presence of sulfuric acid to form alkyl borate, this chemical reaction uses for quantitative chemical analysis of borates.
H2BO3 + 3C2H5OH → B(OC2H5)3 + 3H2O
On fusion with metal oxides colored borate glasses formed and with NH4HF2 ultimately BF3 obtained. Therefore, H3BO3 acts as a strong acid in anhydrous sulfuric or nitric acid solution. Treatment of H3BO3 with sodium peroxide or hydrogen peroxide gives sodium or mono peroxo-borates. Therefore, the structure of peroxoborate ion is [B2(O2)2(OH)4]-2 in which two tetrahedral sp3 hybridized orbitals of boron bonding by bridging μ-peroxo groups.
Uses of Boric Acid Powder
Boron and boric acid are extensively used in the modern age as reinforcement materials in space shuttles and aircraft, in the textile chemical industry for making borosilicate glass, for the preparation of enamels of our teeth, we use shining H3BO3 and borax powder.
Over a hundred years, boric acid has been used for the treatment of vaginal suppositories or infection and commonly used by physicians and patients as an antiseptic, antibacterial in medicine or treatment of candidiasis and BV. Sodium perborate which is prepared from H3BO3 uses for detergent preparation in the chemical industry and boron carbides and metal borides extensively used as neutrons shielding chemical and control rods in nuclear plants. We used boric acid in the carrom board, in the preservation of food grains like wheat and rice from the insecticides mainly cockroaches.