Hydrochloric acid is also called muriatic acid and is chemically represented as HCl.
It is a monobasic acid and hence, it releases only one hydrogen atom when dissolved in water.
The hydrochloric acid uses include
- In stomach
- To make aqua regia
- To generate Hydrogen gas
- In the manufacture of inorganic chemicals.
- In wastewater treatment.
- To clean ion exchange resins.
- For removal of metal stains
- Large-scale production of polymers.
- In preparation for disinfectants.
- In metallurgy
- Laboratory reactions like titrimetry
- In the extraction of petroleum.
- For purification of table salt.
- Purification of sugar
- Tanning of leather
- For electric batteries
- As disinfectant at homes.
- In medicine for achlorhydria
HCl is an ionic compound of Hydrogen chloride. HCl gas has a distinctively pungent smell, but when hydrogen chloride gas is dissolved in water to give hydrochloric acid, it becomes odorless. It is also called muriatic acid.
HCl = H+ + Cl–
Like Hydrobromic acid, Hydrochloric acid is a strong inorganic acid. It is a corrosive acid and colorless.
Uses of hydrochloric acid
1. In the stomach
Hydrochloric acid is released in the stomach by parietal cells of the gastric glands. This acid lowers the pH of the stomach, creating an acidic medium due to which the gastric enzyme pepsin gets activated.
It is also responsible for killing many harmful microbes that enter the stomach along with the food.
It also helps in the absorption of the iron elements from food.
2. To make Aqua Regia
Aqua regia is a miture of two strong acids viz. the HCl and Nitric acid.
So, hydrochloric acid is used along with nitric acid in the production of aqua regia.
For every three parts of hydrochloric acid, one part of nitric acid is used.
This aqua regia is a yellow fuming liquid, and can dissolve inert metals like gold or platinum.
It is used to clean jewelry or other items made of gold and also glassware.
3. For generation of Hydrogen gas
Hydrogen can be produced by corrosion of aluminum in Hydrochloric acid at different temperatures.
4. To make inorganic chemicals.
Hydrochloric acid is used to make many inorganic chemicals like poly aluminum chloride (PAC), iron (III) chloride, ferric acid(H2FeO4), etc.
5. In wastewater treatment
HCl is a common chemical used in wastewater treatment. HCl is used to adjust the pH of water.
It is used as an emulsion breaker in wastewater coming from industries. Since HCl is a powerful corrosive, it is also used to remove scale formation due to the salts in water.
6. For resin regeneration
Ion exchange resins are used for separation and purification of substances.
HCl is used in the regeneration of ion exchange resins as it can rinse away the cations from the resins.
Thus this reduces cost. The ion exchange method is used to remove the permanent hardness in water and convert it into soft water.
7. To remove metal stains
As it is a corrosive acid, it can be used to remove metal stains.
It can also be used to watch metal surfaces. It can be used on metals like iron, copper, or alloys like brass. It is used to clean the layer of rust formed on metal objects.
But as it is a very strong acid solution, it should be highly diluted with water; otherwise, the acid can eat through the metal and ruin the object.
Thus HCl is a powerful cleaning agent.
8. Polymer production
HCl is used to make various useful polymers. In the chemical industry, it is used in the large-scale production of PVC or polyvinyl chloride (CH2CHCl).
It is used to produce polyurethane or to make plastic from starch. It is also used to make bisphenol A, which is used to produce plastic.
9. Production of chlorine-based disinfectants.
Hydrochloric acid is used in chlorine dioxide synthesis.
Chlorine dioxide is a powerful disinfectant. It is commonly used as a bleaching agent.
2NaClO3 + 4HCl -> 2ClO2 + Cl2 + 2NaCl + 2H2O
10. For metallurgic extraction
Hydrochloric acid is used in various metallurgical processes like extraction of alumina, titanium dioxide, etc.
11. In the laboratory
HCl is a strong acid and is commonly used in the determination of alkalies by acid-base titrations.
It is also used for the identification of cations in salts and also to provide an acidic medium to facilitate specific reactions.
12. Extraction of petroleum
Hydrochloric acid is used for the production of mineral oil (petroleum) and desulfurisation.
HCl acid is injected into a rock that may contain oil. The HCl acid acts like a corrosive and forms large-pore structures in the rock.
This assists in oil production and extraction of oil.
Further, presence of sulfur in petroleum products is a environmental concern. The desulfirisation process removes it.
13. Purifying table salt
This acid is used to purify table salt sodium chloride (NaCl).
In this method, the impure salt is dissolved in water to ionize into sodium and chloride ions.
Then the HCl is dissolved in water which also ionizes into H+ and Cl–.
Thus, the chloride ion is common and due to the common ion effect, NaCl ionization gets suppressed, and deposition of pure NaCl takes place.
14. In Industries
HCl is used to regulate the acidity level or pH of industrial solutions.
It is used to control and change the pH of commercial items like food or pharmaceutical products.
Hence, you will notice many medicine constituents are present as hydrochloride salts.
15. To Purify sugar
It’s used to purify sugar. We can extract xylose and glucose by acid hydrolysis of sugarcane juice. The other organic substances in the solution are removed by hydrochloric acid. This gives a solution in which the sugar concentration is more.
16. To process leather
It is used in the leather tanning industry to process leather. HCl is used by tanneries to prevent the growth of bacteria on the leather as HCl can change the pH.
17. As disinfectant at home
Hydrochloric acid is a powerful disinfectant and is commonly used for cleaning kitchens and bathrooms.
It can reduce the pH and prevent the growth of bacteria.
18. To clean mansions
HCl is used to clean completed brick structures by masons as it is a corrosive acid.
19. In batteries
Hydrochloric acid is also used to make batteries as it is a powerful acid and dissociates readily to give hydrogen ions which act as charge carriers and complete the circuit generating current.
20. As medicine
Achlorhydria is a condition wherein a person has an insufficient secretion of hydrochloric acid in his stomach.
In such cases, dilute HCl is used as medicine.
- Aqua regia
- Ion exchange resin
- Recrystallizations and Extractions of Organic Compounds
- Desulphurization study of petroleum products
- The common Ion effect