Boric acid

From CreationWiki, the encyclopedia of creation science

Revision as of 23:45, 15 March 2009

This article is a work in progress by a student at Cedar Park Christian Schools.
Please do not edit the article until this banner is removed.

Boric acid
General
Systematic name	boric acid trihydroxidoboron
Other names	Orthoboric acid, Boracic acid, Sassolite, Optibor, Borofax
Molecular formula	B(OH)3
SMILES	OB(O)O
Molar mass	61.833 g/mol61.833 amu
Appearance	White crystalline solid
CAS number	10043-35-3
Properties
Density and phase	1.435 g/ml, solid
Solubility in water	5.7 g/100 ml (25°C)
Melting point	169°C (decomp.)warning.pngUnit conversion for unit "°C(decomp.)" not supported.
Boiling point	300°C (decomp.)warning.pngUnit conversion for unit "°C(decomp.)" not supported.
Acidity (pKa)	9.24
Structure
Molecular shape	Trigonal planar
Crystal structure	triclinic
Dipole moment	0 D
Hazards
MSDS	Material Safety Data Sheet
Main hazards	Irritant in case of skin or eye contact
NFPA 704	0 1 0
Flash point	nonflammable
R/S statement	R: 36, 38, 40, 62 S: 24, 25
RTECS number	ED4550000
Related compounds
Related compounds	Boron trioxide, Borax
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Disclaimer and references

Introduction

Boric acid was first prepared by Wilhelm Homberg (1652-1715) from borax, by the action of mineral acids, and was given the name sal sedativum Hombergi ("sedative salt of Homberg")[1] Boric acid and its sodium borate salts are active ingredients of pesticide products used against insects, spiders, mites, algae, molds, fungi, and weeds. They were first registered as pesticides in the United States in 1948 and reregistered in [npic.orst.edu/factsheets/borictech.pdf]

Properties

The term boric acid refers to three compounds: metaboric acid ((HBO₂ or B₂O₃·H₂O)), tetraboric acid (H₄B₄O₇ or B2O3·H2O), and orthoboric acid (H₃BO₃ or B₂O₃·3H₂O). Both metaboric and tetraboric acid form when orthoboric acid dehydrates above 170°C and 300°C. When metaboric acid and tetraboric acid dissolve, they revert back to the original orthoboric acid.[2] Thus, orthoboric acid is the main compound referred to by the term boric acid. [3] This compound is generally found as a crystalline powder. The crystal structure of the acid is triclinic, meaning its crystal system has 7 lattice points.[4] The layers of of molecules are held together by hydrogen bonds. Two adjacent layers of molecules are connected by 318 pm. of hydrogen bonds.[5] Boric acid is usually white, but its color ranges from clear to opaque.[6] It is poorly soluble in room temperature water, but easily dissolves in hot water, alcohol, and glycerine.[7] This hygroscopic compound is odorless and usuallu stable, but is slightly volatile in steam.[8] Boric acid is not a strong acid, but is considered acidic due to its interaction with water molecules.[9][10]

Occurrences

Boric acid has been found in natural steam vents, such as this one located in Hawaii

Boric acid is found in a variety of resources. Because it is derived from boron, a naturally occuring element, it can be found in nature as well as in the scientific laboratory.[11] The major source of boric acid is in volcanic areas, such as at steam vents or volcanoes. In Tuscany, the Lipari Islands, and Nevada, the free acid has been found mixed with steams from fissures in the ground.[12][13] Boric acid is a common constituent of several minerals such as borax, boracite, boronatrocaicite and colemanite. Many plants and almost all fruits have been reported to contain boric acid. Its presence and the presence of its salts have even been detected in seawater, where it contributes to the absorption of low frequency sound. Borax is also easily created in a laboratory by treating borax with sulfuric acid or by the action of mineral acids.[14][15]

Uses

Boric acid is a versatile compound that serves a variety of unique purposes throughout history. In ancient times, the Greeks used it to fireproof cloth. In the late 1800's and early 1900's, it was used as a food preservative until its harmful effects were discovered. It even was used as an ingredient for diaper rash creams, but babies became sick because of it.[16] Despite its mildly hazardous qualities, it is still used today. Mainly, it is used to make borate salts, such as borax.[17] However, it serves a large variety of other purposes as well.

Medicinal

When boric acid is in a solution, it is only slightly acidic. Therefore, it can be used for both cosmetic and medicinal purposes. In a solution, it is utilized as an astringent antiseptic for minor burns or cuts. [18] It's even mild enough to be used as an eyewash, acne treatment, and emulsifier. [19][20][21] Boric acid in solution is only slightly acidic and acts as a nonirritating, slightly astringent antiseptic, mild enough to be used as an eyewash. It also treats yeast and fungal infections, including athlete's foot.[22]

Preservation

Because boric acid is hygroscopic, it takes moisture from the air. This property allows it to prevent and destroy fungal growth both in citrus fruits and rot in wood. In combination with an ethylene glycol carrier, boric acid can protect the wood against fungal and insect attack.[23]

Nuclear

Boric acid is also used in nuclear power plants. It acts to slow down the rate of fission. The rate of fission depends on how many neutrons are present. Boric acid, when circulated throughout the nuclear reactor, reduces the probability of a neutron's survival. Thus, this hinders the rate of fission. [24]

Commercial Use

Boric acid plays a role in many commercial industries. The jewelry industry uses boric acid to create artificial gems and to protect the beauty of jewelry during smoldering. When combined with alcohol, it can reduce surface oxidation and firescale from forming on metals during certain operations.[25] It is also used in the production of steel, fiberglass, and glass, such as LCD flat panel displays.[26][27] The boron fibers add a high, tensile strength to the material to mate it strong. Ceramic companies use boric acid to reduce the melting point of the product and prevent cracking or distortion. In this way, it is an essential ingredient for both the ceramic product and its glaze.[28] Another important commercial use of boric acid is its ability to make cloth and other products flame-retardant.[29]

Other

Aside from the main uses of boric acid, the compound also serves in unexpected areas such as pyrotechnics , toys, and even Indian games. For example, Silly Putty, a popular product for children, was originally made by mixing silicone oil and boric acid. Boric acid is also added to fireworks to prevent an amide-forming reaction between aluminium and nitrates. Indians dust Carrom boards with boric acid to reduce friction. When added to salt, boric acid can help in the curing of cattle hides and other skins. [30][31]

Insecticide

Many insecticides, such as this one, incorporate boric acid.

Mixtures with boric acid attract insects that will die after ingesting the compound.

Boric acid was first registered in the US as an insecticide in 1948 for control of cockroaches, termites, fire ants, fleas, silverfish, and many other insects.[6] It acts as a stomach poison affecting the insects' metabolism, and the dry powder is abrasive to the insects' exoskeleton.

Boric acid is generally considered to be safe to use in household kitchens to control cockroaches and ants. Homemade ant bait can be made by dissolving 1 teaspoon (5 mL) powdered boric acid and 10 teaspoons (50 mL) sugar into 2 cups (500 mL) of water; this mixture can then be absorbed into cotton balls which are left near ant trails. This reportedly will be carried back into the ants' nest, killing any ants that eat it, potentially destroying the entire colony.

Boric acid is also made into a paste or gel form. The paste or gel has attractants in it to attract insects; mostly cockroaches. It is convenient to use because you can simply put a small dab under sinks, counters, refrigerators, and stoves. The boric acid dehydrates the insects. It does it slowly and they don't realize they are in danger. One of the real benefits of using boric acid is that immunity can't be built up; since it works through dehydration. The insects take the bait back to the nest and one application can eliminate them for an entire year.

Boric acid is generally known as a desiccant; in other words, it kills by removing the moisture from the body of the target pests, causing severe dehydration which will affect electrolyte metabolism with the potential of metabolic acidosis. In fact, boric acid is a stomach poison normally ingested, along with the fact that it can also enter the blood by inhalation. Boric acid is an acid. Acid will decrease the pH level with the possible side effects of renal, respiratory, and cardiovascular failure. Symptoms and signs of boric acid poisoning are nausea, vomiting, diarrhea, headache, dysphagia, cold sweats, dyspnea, muscular debility, scarlatinal eruptions, subnormal temperature, cardiac weakness, cyanosis, coma, collapse, etc. Boric acid is 3 parts hydrogen, 1 part boron, and 3 parts oxygen. Recently U.S. Borax discovered that boric acid contains traces of arsenic. Before California Prop 65 there were few, if any, human studies on boric acid. When human studies were requested from U.S. Borax they said they were unable to supply us with any at that time. But in the late 1980's they had started doing new and extensive toxicity tests on rats and mice as a result of California Prop 65. As a result of these tests, they discovered a decrease in sperm count and the stopping of fetal and embryonic development in rats and mice. In early 1993, U.S. Borax had asked for, and has received, additional time to complete their laboratory studies from the State of California. [32]

References

• Safety data for boric acid The Physical and Theoretical Chemistry Laboratory.

Oxford University

• Boric acid Wikipedia.org.
• Boric Acid Chemicalland21.com.
• Opinion & Information on Boric Acid By Michael R. Cartwright, Sr. Dvfmastiff.net.
• Borichtech. National Pesticide Information Center.
• Boric acid history People For Clean Beds.org.
• Boric Acid Microsoft® Encarta® Online Encyclopedia 2008.
• Boron & compounds fact sheet Australian Government. Department of the Environment, Water, Heritage, and the Arts.
• reference title description (i.e. source, website, author, etc.)

v • d • e Chemistry Featured articles Atom • Biotechnology • Bonds • Chemical series • Substances • Compounds • Electrons • Energy • Elements • Ion • Microscopy • Nuclear chemistry • Nuclear weapon • Organic compound • Periodic table • Radioactive decay Compounds Acid • Alcohol • Amine • Amino acid • Anion • Base • Carbohydrate • Chloride • Carboxylic acid • Hydrocarbon • Hydroxide • Inorganic compound • Ion • Isomer • Lipid • Nucleotide • Nitrate • Organic • Phenol • Polyatomic ion • Protein • Resonance structure • Salt • Sugar • Sulfate • Sulfide Categories • Portal