Methods of Preparing Boric Acid

1. METHODS OF PREPARING
BORIC ACID,
PROPERTIES AND
APPLICATIONS
Instructor: Milgrace E. Nonesa ,RPh

2. Boric acid
 Very weak acid with the formula;
BH3O3 , H3BO3 or B(OH)3.
 Other Names : Boracic acid , Orthoboric acid ,
Borofax
 used as a mild antiseptic in the medical field.
 As a chemical compound
 Boric acid acts as a tribasic acid.
 It dissociates to such a small extent, it is a very
weak acid that is actually used in water solution
as an eye wash.

3. Boric acid
 Pure boric acid is a colorless, odorless, white
powder or transparent crystals with a slightly oily
feeling that slowly decomposes with heat at about
340°F (171°C).
 Boric acid loses water as it is heated, changing
first into metaboric acid (HBO2) and then into
pyroboric acid (H2B4O7) and eventually to boric
oxide (B2O3). The three acids can be thought of as
hydrates of boric oxide (B2O3).
 Orthoboric acid is fairly soluble in water
(especially hot water), alcohol, and glycerine.

4. Boric acid

5. PROPERTIES OF BORIC ACID
 white solid that crystallizes from aqueous solutions as
triclinic waxy plates.
 The crystal structure of boric acid consists of planar
sheets of planar trigonal B(OH)3 molecules linked by
hydrogen bonds.

6. APPLICATIONS OF BORIC ACID
IN OUR DAILY LIFE
 Most important uses of Boric acid is as a source of
Boron Trioxide B2O3 in glasses & other vitreous
products, fiberglass, heat-resistant borosilicate
glasses, ceramic glazes, porcelain, ceramics,
crockery, enamels, artificial gemstones, and sealing
and optical glasses.
 Boric acid has other applications like
 insecticide for cockroaches,
black carpet beetles
fungicide on citrus fruits.

7. In the medical field
 boric acid has extensive use in:
 mouthwashes
 nasal sprays
 eye-hygiene formulations.
 Boric acid can also be used as a fire-retardant
in some occasions. Other important applications
include preservatives for natural products such
as wood and natural fibers.

8. AVAILABILITY OF BORIC ACID IN NATURE
 In nature, Boric acid exists in two forms, a
 Glassy form
 obtained by high temperature dehydration of boric acid,
 Crystalline form
 obtained by slow heating of metaboric acid. Boric acid occurs
naturally in a number of locations where it has precipitated out of
hot springs. It may occur then in the form of the mineral sassolite.

9. PRODUCTION OF BORIC ACID
• The most common method
of producing boric acid is
by :
• treating the relatively
abundant borax with
hydrochloric or sulfuric
acid
• crystallizing out the
boric acid that forms in
the reaction.

10. PRODUCTION OF BORIC ACID
A less common method of preparation
involves the treatment of borax brine
solutions with a chelating agent that
binds to the borates present in the
brine, which can then be converted to
boric acid.

11. PRODUCTION OF BORIC ACID
 Boric acid can be prepared in the laboratory by :
Acid hydrolysis of a variety of boron compounds,
including halides, esters, salts, and hydrides.
 Boric acid is produced commercially by reactions of sulfuric
acid with sodium borates, and with sodium and calcium
borates or by reaction of sulfuric acid with: ulexite, a mixed
sodium-calcium borate.
 Ulexite is a structurally complex mineral, with a basic
structure containing chains of sodium, water and
hydroxide octahedral. The chains are linked together
by calcium, water, hydroxide and oxygen polyhedra
and massive boron units.

12. PRODUCTION OF BORIC ACID
 Boric acid is also produced from the borosilicate
mineral datolite.
 Datolite is
a calcium boron hydroxide nesosilicate, CaBSiO4(O
H). It was first observed by Jens Esmark in 1806,
in allusion to the granular structure of the
massive mineral. Datolite crystallizes in
the monoclinic system forming
prismatic crystals and nodular masses. The luster
is vitreous and may be brown, yellow, light green
or colorless.

13. FACT OF BORIC ACID
 DIFFERENT NAMES OF BORIC ACID
Orthoboric acid, Hydrogen orthoborate, Boracic
acid
 FORMULA OF BORIC ACID
H3BO3
 ELEMENTS OF BORIC ACID
Hydrogen, boron, oxygen
 Compound Type of Boric Acid INORGANIC ACID
 Physical State od Boric Acid Solid

14. FACT OF BORIC ACID
 MOLECULAR WEIGHT OF BORIC ACID
61.83 g/mol
 MELTING POINT OF BORIC ACID
170.9C (339.6F)
 BOILING POINT OF BORIC ACID
Decomposes above its melting point
 SOLUBILITY OF BORIC ACID
Soluble in water, ethyl alcohol, and glycerol
 TOXICITY OF BORIC ACID
Boric acid is toxic if swallowed

16. METHODS OF PREPARING
HYDROBROMIC ACID,
PROPERTIES AND
APPLICATIONS

17. What is Hydrobromic Acid?
 Powerful acid formed in water by dissolving bromides
of hydrogen.
 Diatomic molecule with the chemical formula of HBr.
 Hydrogen bromide is a colorless, suffocating gas, very
soluble in water and highly dissociated in aqueous
solution. It readily fumes in the presence of moist air.
 Hydrogen bromide gas are highly corrosive substances
that can cause severe burns upon contact.
Other names – Hydrogen bromide, bromane

18. What is Hydrobromic Acid?
HBr Hydrobromic Acid
Density 1.49 g/cm³
Molecular Weight/
Molar Mass
80.9119 g/mol
Boiling Point 122 °C
Melting Point -11 °C
Chemical Formula HBr

19. Hydrobromic Acid Structure – HBr

20. Physical Properties of Hydrobromic Acid – HBr
Odour Pungent irritating odor
Appearance Colorless/faint yellow
liquid
Covalently-Bonded Unit 1
Heat capacity 29.1 J/(K·mol)
Hydrogen Bond Donor 1
Solubility Soluble in water

21. Chemical Properties of Hydrobromic Acid – HBr
Hydrobromic acid reacts with
sulfuric acid forming sulfur dioxide,
bromine and water. The chemical
equation is given below.
2HBr + H2SO4 → Br2 + SO2 + 2H2O
Hydrobromic acid reacts with propene
undergoe addition reaction resulting in the
formation of 2-Bromopropane. The chemical
equation is given below.
HBr + C3H6 → C3H7Br

22. Uses of Hydrobromic Acid – HBr
 Used as a chemical intermediate, the major
uses for elemental bromine are as a sanitizing
or disinfecting agent.
 Used as a reagent and as a catalyst in a variety
of organic reactions.
 Used in the preparation of numerous organic
compounds.
*Anhydrous hydrobromic acid is hazardous and
shipped in high pressure cylinders.