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How many of you can say you haven't had a cola drink at least once in your life?
Some of you may be completely in love with such drinks, while others may have a strong aversion to them. When it comes to the cola-craze, some of you may even fall into the balancing zone!
Whatever the case may be, did you know that the special tanginess and delicacy in any of your cola drinks is owed to one special component- "Phosphoric acid"?
Yes, indeed. Phosphoric acid is responsible for the flavour of cola drinks.
Citric acid replaces phosphoric acid in other non-alcoholic beverages except for cola drinks. Phosphoric acid is also found in numerous sports drinks, bottled teas, and fruit-flavoured drinks, in addition to cola drinks.
In a 2006 study published in the American Journal of Clinical Nutrition, researchers discovered that cola, not carbonated beverages, causes osteoporosis in women and that phosphoric acid can harm bone health. Some epidemiological studies, including one published in the American Journal of Clinical Nutrition, have connected phosphoric acid to reduced bone density.
On the contrary, other research has found that a low phosphorus intake causes decreased bone density. Guess who paid for the research? PepsiCo.
TABLE OF CONTENTS
Phosphoric acid is an oxoacid of phosphorus with four oxygen atoms, one phosphorus atom, and three hydrogen atoms. It is also known as phosphoric(V) acid or orthophosphoric acid. It is found in teeth and bones, and it helps in metabolic processes. It appears as a clear, colourless solution in liquid form and as a transparent, crystalline solid in solid form.
Orthophosphoric acid (H3PO4) is one of the most popular acids that is used in many industries, especially in the manufacturing of fertilisers. The salts of this acid are known as phosphates.
Phosphoric acid is a triprotic acid in nature with three donatable protons. It aids in the binding of divalent cations as a sequestering agent. It is extensively used in orthodontics and dentistry. Phosphoric acid has an important role in biogeochemistry and biochemistry.
It ionises to give three H+ ions. Hence, its basicity is 3. All three hydrogens are acidic, with pKa1=2.14, pKa2=7.20, and pKa3=12.37 for the first, second, and third hydrogens, respectively.
The structural formula is PO-(OH)3 or H3PO4 is used to characterise it and the hybridisation of phosphorus in orthophosphoric acid is sp3. The geometry of orthophosphoric acid is tetrahedral. A double bond holds the core phosphorus atom and an oxygen atom together. Through single bonds, it is additionally attached to three hydroxyl (-OH) groups.
Fluorapatite contains phosphate minerals, which are used to make phosphoric acid (a naturally occurring crystal rock). Fluorapatite reacts with concentrated sulphuric acid and water. As a result, phosphoric acid (H3PO4) and calcium sulphate, as well as other contaminants, are generated. The excess chemical compounds and contaminants are removed using the filtration and evaporation processes.
P4 + 5HNO3 → H3PO4 + H2O + 5NO2
Ca5(PO4)3X + 5H2SO4 + 10H2O → 3H3PO4 + 5CaSO4.2H2O + HX
Where X = F, Cl, Br, -OH
P4O10 + 6H2O→ 4H3PO4
H3PO4 ⇌ H2PO4- + H+, pKa1 = 2.14
H2PO4-⇌ HPO42- + H+, pKa2 = 7.20
HPO42-⇌PO43- + H+, pKa3 =12.37
Orthophosphoric acid is an important chemical with a wide range of applications in a variety of industries, agriculture, and everyday products. In any event, we will look at some of the most common applications of phosphoric acid.
Rust Removal
In Food and Beverage
In Agriculture
Personal Care
Pharmaceutical Industry
Other Applications
The phosphoric acid in soft drinks has the potential to cause tooth erosion. Phosphoric acid may also contribute to the production of kidney stones, especially in people who have previously experienced kidney stones.
Concentrated sulphuric and nitric acid are more corrosive and dangerous than phosphoric acid. But concentrated solutions of phosphoric acid irritate the skin and mucous membranes. P2O5 fumes in the vapours can irritate the throat and induce coughing. However, at 10 mgm-3 they might be tolerated.
Phosphoric acid, in both solid and liquid form, is non-combustible. If inhaled, it can be lethal. Phosphine, phosphoric acid, and hydrogen chloride, which are found in fire smoke, can irritate respiratory tracts, eyes, and skin.
At low quantities, phosphoric acid is non-poisonous and does not harm the skin or any other part of the body. Even in higher dosages, it's harmful since it irritates the skin and can even harm the eyes.
If the vapours of H3PO4 are breathed in, it can also disrupt the respiratory system. Hence, this acid should be stored in a metallic or covered fibreboard compartment (with a polyethene internal bundle) and kept cool and well aired.
Q1. Phosphoric acid is used as an electrolyte in which type of cell?
A. Voltaic Cell
B. Hydrogen Cell
C. Diesel Engine
D. Fuel Cell
Answer: Phosphoric acid is used in fuel cells. Phosphoric Acid Fuel Cells (PAFCs) operate at temperatures ranging from 150 to 200 degrees Celsius (about 300 to 400 degrees F). The electrolyte in PAFCs is phosphoric acid, as the name implies. From the anode to the cathode, positively charged hydrogen ions migrate through the electrolyte.
So, option D) is the correct answer.
Q2. Phosphoric Acid serves as a
A. Food Additive
B. Leavening Agent
C. Emulsifier
D. Food Colourant
Answer: Acidifying foods and beverages, such as colas and jams, with food-grade phosphoric acid gives them a tangy or sour taste. The phosphoric acid acts as a preservative as well. Soft drinks that include phosphoric acid, such as Coca-Cola, are known as phosphate sodas or phosphates. As a result, it is a food additive.
So, option A) is the correct answer.
Q3. Orthophosphoric acid has the basicity of
A. 1
B. 3
C. 0
D. 2
Answer: Orthophosphoric acid (H3PO4) is a tribasic acid with three donatable hydrogen ions (Phosphoric acid or H3PO4 can release up to three H+ ions). So, its basicity is 3.
H3PO4 ⇌ H2PO4- + H+, pKa1 = 2.14
H2PO4-⇌ HPO42- + H+, pKa2 = 7.20
HPO42-⇌PO43- + H+, pKa3 =12.37
Q4. Phosphoric acid is an efficient
A. Oxidising agent
B. Dehydrating agent
C. Reducing agent
D. Hydrating agent
Answer: Phosphoric acid acts as a dehydrating agent. Phosphoric acid, most commonly in the form of polyphosphoric acid, is a potent dehydrator. It is the anhydride of phosphoric acid that captures OH through the creation of a HO-P bond.
Question 1. What happens on heating phosphoric acid?
Answer: The orthophosphoric anhydrous acid is a crystalline white solid with a melting point of 42.3 °C. There will be a loss of component oxygen when phosphoric acid is heated to temperatures of roughly 200 °C. Dehydration creates a series of acids, from pyrophosphoric acid (H4P2O7) through metaphosphoric acid (H4P2O8).
Question 2. Why is phosphoric acid added to cola?
Answer: Phosphoric acid is a colourless and odourless crystalline liquid. It delivers soft drinks with a tart flavour while also preventing the growth of mould and germs, which may easily flourish in a sugar solution. The phosphoric acid in soda contributes a significant amount of its acidity. It is then treated again to become phosphoric acid.
Question 3. Is phosphoric acid capable of dissolving rust?
Answer: Few stronger acids will completely eradicate rust, but they will etch and pit the surface of any remaining ferrous metal, weakening it. One of the few acids that may eliminate rust without oxidising or damaging the iron beneath it is phosphoric acid.
Question 4. Can phosphoric acid be used as a disinfectant?
Answer: Bowl cleanse is a phosphoric acid solution that disinfects toilet bowls and urinals by removing dangerous microorganisms. The 25 % phosphoric acid solution removes mineral particles from toilets rapidly and without causing damage to the pipes.
Related Topics
Allotropes of Phosphorus |
Oxygen |
Phosphorus halides |
Potassium |
Phosphine |
Alkali Metals |