Phosphoric Acid (H3PO4) Uses, Benefits, Side Effects and Facts

Phosphoric acid, also known as H3PO4 and ortho-phosphoric acid, is a colorless, odorless liquid mineral acid with a syrupy consistency that is only soluble in water and ethanol. It is added to soft drinks to give them a sharper flavor. Almost all of the acidity of soda pop comes from the phosphoric acid. It also slows the growth of molds and bacteria, which would otherwise multiply rapidly in the sugary solution. It is also used as a rust converter (often called naval jelly or rust killer) for converting rust into ferric phosphate. Thus it is efficient for removing rust. It is a chemical which is produced in large quantities in food industry. It is cheaply produced.

Some Quick Facts about Phosphoric Acid

1. Phosphoric acid is a clear, colorless, odorless liquid with a syrupy consistency.

2. Phosphoric acid is used as an acidifying agent to give colas their tangy flavor.

3. Due to the use of phosphoric acid, cola is a actually more acid than lemon juice or vinegar. The vast amount of sugar acts to mask and balance the acidity.

4. Phosphoric acid also goes by E338, orthophosphoric acid, and phosphoric(V) acid.

5. Food-grade phosphoric acid is a mass-produced chemical, available cheaply and in large quantities.

6. Phosphoric acid is commonly used for rust removal.

7. Phosphorus-containing substances occur naturally (0.1%-0.5%) in foods such as milk, meat, poultry, fish, nuts, and egg yolks.

8. Phosphoric acid has been linked to lower bone density in some epidemiological studies, including a discussion in the American Journal of Clinical Nutrition.

9. Opposing studies showed the opposite – that "low" intake of phosphorus leads to lower bone density. Guess who funded the studies? PepsiCo.

10. Aside from the risk of osteoporosis, Cola consumption has also been linked to chronic kidney disease and kidney stones.

11. According to the Center for Science in the Public Interest (CSPI), a consumer watchdog group not affiliated with the food industry, only a small fraction of the phosphate in the American diet comes from additives in soft drinks. Most comes from meat and dairy products. So your reason for not drinking Coke should be its sugar content and artificial food colorings, not the phosphoric acid.

12. About 10 million tons of phosphoric acid are produced in the U.S. each year. Most of the

acid (about 80%) is used in the production of agricultural fertilizers, with the remainder being used for detergent additives (about 10%), cleaners, insecticide production, and cattle feed additives.

Phosphoric Acid Uses and Benefits

Phosphoric acid has varied uses. In manufacturing, it is a chemical intermediate or reagent in the production of numerous phosphate fertilizers, agricultural feeds, waxes, polishes, soaps, and detergents. It is added to foods as a preservative, acidifying agent, flavor enhancer, and clarifying agent. Phosphoric acid is also used in processes such as the coagulation of rubber latex, electropolishing, soil stabilization, and as a catalyst in the production of propylene and butene polymers, ethylbenzene, and cumene. By far, largest use of phosphoric acid comes in the production of fertilizers (around 85%). Airborne phosphoric acid can be produced by the hydrolysis of phosphorus oxides generated from either the spontaneous ignition of white phosphorus in air or the combustion of red phosphorus.

Phosphoric acid is used most commonly in laboratory preparation of hydrogen halides. It is also used as a rust converter (often called naval jelly or rust killer) for converting rust into ferric phosphate. Thus it is efficient for removing rust. It is a chemical which is produced in large quantities in food industry. It is cheaply produced.

It can be used for providing sour or tangy taste to the processed food. Sometimes it is used for the extraction of citric acid in food industry. It is used in the medical field, basically by the dentists for the correction of irregularities of the teeth (orthodontics) and for dealing with the anatomy, development and diseases of the teeth (dentistry) as an etching solution. It is also used as a teeth whitener to eliminate plaque. It is also the basic constituent in over-the-counter anti-nausea medications which contains high levels of fructose and glucose.

Stating the industrial uses, phosphoric acid is also used as an external standard for phosphorus-31 nuclear magnetic resonance (NMR). In the industrial area it is required for the process used for separating mixtures due to differences in absorbency that is chromatography. It is useful in making phosphoric acid fuel cells, where in it is used as the electrolyte. If one puts two to three drops of phosphoric acid in a gallon of distilled water, it acts as electrolyte in oxy-hydrogen generators.

Copper electro polishing is done by using phosphoric acid as an electrolyte. Also this form of phosphoric acid as an electrolyte is used for circuit board planarization and for filing rough edges on work piece. While carrying out the Wentworth Process for activated carbon production, phosphoric acid is used as oxidizing agent.

It is a wet etching agent and hence is commonly used to make impressions on surface. To etch silicon nitride hot phosphoric acid is used in micro fabrication. Due to its defined properties phosphoric acid is also used by construction traders as a cleanser to remove mineral deposits on the sites. It can be used for removing hard water stains as well. It is also used as an aid to soldering in for example in model rail roaders. Phosphoric acid should be stored in a tight container and the area around should be cool, dry and well ventilated.

Hence phosphoric acid is a chemical having abundant uses in industrial applications.

Phosphoric Acid Side Effects

Toxicity & Dangers

Phosphoric acid is corrosive to the eyes, skin and respiratory tract and corrosive upon ingestion. The risks for man and for the environment are therefore mainly due to the corrosive nature of phosphoric acid when in contact with this chemical. Concentrated solutions of phosphoric acid result in severe lesions of the tissues. Diluted solutions are only moderately irritating; repeated or prolonged contact with the skin can cause dermatitis.

During combustion, toxic fumes form, consisting of phosphorous oxides. The substance breaks down when in contact with alcohols, cyanides, ketones, phenols, esters, sulphides and halogenated organic substances, producing toxic fumes.

Toxicological Data

Concentrated solutions of phosphoric acid result in severe lesions of the tissues with which they come into contact, while diluted solutions of phosphoric acid are only moderately irritating. The intensity and nature of the lesions caused will depend on the concentration of the acid and the duration of exposure.

Seek medical attention right away if any of these SEVERE side effects occur when using Phosphoric Acid Solution: Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue).

Acute Human Toxicity

-By inhalation: causes severe irritation of the upper respiratory tract, accompanied by a cough, burns, breathing difficulties and a risk of coma. Can cause irritation liable to trigger pulmonary congestion by chemicals and pulmonary oedema.

-By ingestion: causes acute pain, nausea, vomiting and diarrhoea. There is also a risk of haemorrhage of the digestive tract, which may lead to corrosion and permanent destruction of the tissues of the oesophagus and digestive tract.

-By skin contact: all contact with the liquid is corrosive and causes severe burns, redness and ulceration.

-By eye contact: risk of irreversible corneal lesions. Contact with this chemical is corrosive for the eyes and causes severe burns.

Chronic Human Toxicity

-Prolonged inhalation can cause inflammation of the respiratory tract and pulmonary lesions.

-Prolonged or repeated skin contact can cause dermatitis.

-Prolonged or repeated contact with the eyes can cause conjunctivitis.

Fire and Explosion

Phosphoric acid is stable, nonexplosive and nonflammable. However, because of its corrosive action on many metals, a reaction which releases hydrogen, phosphoric acid can be a secondary source of fire or explosion: hydrogen is a highly flammable and explosive gas when mixed with air. In the presence of strong bases, a lot of heat is released with a risk of projections.

Other Side Effects

Phosphoric acid is added to many kinds of soda pop to help keep the carbonated bubbles from going flat. Because good health depends upon our bodies being able to maintain a one-to-one balance between calcium and phosphorus in our systems, calcium is released from our teeth and bones into our bloodstreams to help balance the phosphoric acid in the pop we drink. Eventually the phosphoric acid is excreted, taking with it the released calcium. Thus, a habit of soft drink consumption actually robs our bodies of calcium, leading to a condition known as osteoporosis – soft teeth and weak bones.

Phosphoric acid is also known to neutralize the hydrochloric acid in our stomachs. This is unfortunate, for we need hydrochloric acid to help us digest our food and utilize its nutrients. It is especially required for calcium utilization. So, not only does phosphoric acid leach calcium from our bones, it also prohibits hydrochloric acid from helping to restore it. Bones and teeth just can't win with this stuff in our diet.

In a survey designed to measure the amount of phosphoric acid in twenty different soft drinks, the following were found to contain the highest amounts: Tab, Coke, Diet Coke, caffeine-free Coke, and Mr. Pibb. The formulas may have been changed for the better since this survey was conducted. Read labels. By the way, Pepsi Free, Diet Pepsi Free, Like Cola, 7-Up, and Mountain Dew had no phosphoric acid in them. This, however, does not mean that these products are free from the other problems true of soft drinks.

First Aid Information

The corrosive action of phosphoric acid can appear after a certain delay: it is important to take immediate action.

Immediately remove all soiled or spotted clothes, including shoes.

Intoxication by Inhalation

-Immediately move the affected person into the fresh air and away from the contaminated area.

-Where necessary, apply artificial resuscitation.

-Immediately obtain medical care.

Skin Contact

-Remove contaminated clothing.

-Rinse the skin with plenty of water for at least 15 minutes or have a shower.

-Immediately obtain medical care.

Eye Contact

-Rinse the eyes with plenty of water for at least 15 minutes (if possible remove contact lenses).

-Immediately obtain medical care and consult an eye specialist.

Intoxication by Ingestion

-If the person is fully conscious, rinse out their mouth with water.

-Give the person plenty to drink.

-Do not induce vomiting.

-Immediately obtain medical care.

Where necessary, contact the nearest poison control center.
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