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Muriatic acid, also known as salfumán or strong water, is an aqueous solution of hydrochloric acid (HCl (aq) ) that is obtained by dissolving gaseous hydrogen chloride in water. This gas is produced, among other ways, by the chemical reaction between gaseous hydrogen and gaseous chlorine, and is one of the most widely used strong mineral acids both in industry and in the home, second only to sulfuric acid.
Depending on its application, muriatic acid can have a concentration of from about 3% to about 38% by mass. The latter is the concentration of concentrated hydrochloric acid, and is the maximum concentration that can be obtained from hydrogen chloride in water at room temperature, given its solubility.
Risks of using muriatic acid or hydrochloric acid
Before discussing the multiple ways in which muriatic acid can be used, it is essential to mention the risks that this implies, and take them into account to avoid extremely serious accidents. It goes without saying that its manipulation by children should be avoided at all costs.
Despite being present in many household products, this is a dangerous chemical that can even cause death, so not only should it always be kept out of the reach of children, but it should also be handled with extreme care by adults. , especially the more concentrated presentations.
From a materials handling point of view, HCl (aq) is classified as a corrosive substance to both metals and skin, and is considered a substance to which attention should be paid.
The main risks associated with exposure to hydrochloric acid are:
Skin contact
HCl is corrosive and can cause severe skin burns, especially if it is a concentrated presentation and especially if contact is prolonged.
Ingestion
Ingestion causes burns to the oral mucosa and esophagus. If the acid is not very concentrated (3% to 5%) it will not affect the stomach. However, the ingestion of more concentrated presentations can cause stomach irritation, gastritis and even mucosal bleeding.
Respiratory contact
Sealed hydrochloric acid solutions are in equilibrium with hydrogen chloride in the gas phase, so the vapors released when opening the bottle can be highly irritating to the respiratory tract.
On the other hand, accidental aspiration of the hydrochloric acid solution (in the form of an aerosol, for example) can cause severe burns in the respiratory tract and lungs, causing pulmonary edema and, potentially, death.
Eye contact
Vapors from muriatic acid or hydrochloric acid may cause eye irritation. In addition, direct eye contact with hydrochloric acid can cause corneal necrosis and permanent loss of vision.
Safety measures when using muriatic or hydrochloric acid
Most of the risks of using muriatic acid can be avoided by following these safety recommendations:
- Always wear safety glasses when working with muriatic acid.
- Wear latex or polynitrile gloves to protect hands.
- Use it in well ventilated places to avoid the accumulation of vapors.
- Have plenty of fresh water on hand.
- Prepare a 5% sodium bicarbonate solution to neutralize the acid if necessary, and keep it on hand.
First aid in case of exposure
General measures in case of spillage
When handling and using mineral acids, whether at home or elsewhere, it is advisable to keep a bicarbonate of soda solution on hand to quickly neutralize any spilled acid and to quickly treat any portion of the skin that has been exposed to acid.
Bicarbonate is a harmless substance that can act as a base, releasing carbon dioxide gas when reacting with acids such as HCl according to the following equation:
The observed fizzing is evidence that the neutralization reaction is still going on, so adding bicarbonate until we see no more fizzing helps us know that we have neutralized all the acid.
Measures in case of skin contact
Immediately remove all contaminated clothing. If you have it on hand, neutralize the acid with baking soda. Then wash the affected area with plenty of water.
Measures in case of ingestion
Usually, drinking a couple of glasses of water is enough to dilute the acid to a safe level in the stomach to prevent the development of gastritis and to wash the oral and esophageal mucosa. However, it is preferable to drink a glass or two of milk instead.
Measures in case of inhalation
This is the most dangerous route of exposure. You should go to an open place to get fresh air and seek medical attention immediately.
Measures in case of contact with eyes
Wash immediately with plenty of fresh, running water. Seek medical attention immediately.
Four uses of muriatic acid or hydrochloric acid in the home
Now that we know the risks of using muriatic acid, have covered how to use it safely, and what to do in case of accidental exposure to this chemical, let’s look at its main uses around the home.
1 Muriatic acid is used as a household cleaner
The main use of hydrochloric acid in the home is as a cleaning and stain removing agent. Its corrosive properties as a strong acid allow hydrochloric acid to dissolve or break down many chemicals that are a common cause of many tough stains.
As a cleaner, hydrochloric acid is present in the vast majority of commercial cleaners for:
- toilet cleaning
- Cleaning tiles, ceramics and bathroom tiles
- Brick Mortar Cleaners
It is especially effective for removing metal oxide stains, since most of these oxides are basic substances that react rapidly with hydrochloric acid to form water-soluble salts.
2 For decalcifying pots, kettles and kettles
In places where the tap water is of poor quality and has high hardness (a high concentration of calcium and magnesium ions), it is common for pots and kettles to accumulate a layer of lime on the surfaces in contact with hot water. This is mainly due to the thermal decomposition of the bicarbonate that generates a high concentration of carbonate ions which precipitate with calcium and magnesium in the form of the respective calcareous salts.
This can be particularly serious in some places where the water is not adequately treated before channeling it through the aqueduct. Hydrochloric acid reacts with the lime formed, breaking down the carbonate ions and transforming the lime into soluble calcium and magnesium salts.
The effect is the easy removal of these stains, thus decalcifying the surface of pots, kettles and other types of kettles.
3 It is used in swimming pools for sanitation and regulation of the pH of the water
pH is a logarithmic scale for measuring the acidity of a solution, such as swimming pool water. The lower the pH, the more acidic the water, and the higher it will be less acidic and therefore more alkaline, while if the pH is 7 the solution will be neutral.
The water in a swimming pool should be kept between neutral and slightly alkaline, with a pH in the range of 7.0 to 7.8. Muriatic acid is often used in swimming pools to lower the pH when it is too alkaline (above 7.8).
4 Hydrochloric acid as a drain cleaner
Another common use of muriatic acid that takes advantage of its corrosive properties is to unclog or unclog pipes. As we saw before, hydrochloric acid can break down and dissolve calcareous deposits, making it possible to unclog pipes clogged by the effect of hard water.
On the other hand, it is also capable of breaking down many other chemical substances, both organic and inorganic, allowing it to soften and even dissolve clogs in sewage pipes.
However, great care must be taken when using hydrochloric acid for these purposes, as some reactions can produce gases that increase the pressure within the pipe which can cause the contents of the pipe, including the acid not yet has reacted, it is expelled from the same place where it was added. If care is not taken, this can result in a very dangerous splash of hydrochloric acid on the face or other part of the body. If accidentally inhaled, it may be fatal.
Six industrial uses of muriatic acid or hydrochloric acid
1 Used in the production of plastics
Polyvinyl chloride, or PVC for its acronym in English, is one of the most important plastics in the world. Its synthesis consists of the free radical polymerization of a monomer called vinyl monochloride (CH 2 CHCl). The latter is prepared by reacting acetylene and hydrochloric acid, by means of a hydrohalogenation reaction of alkynes. In this sense, hydrochloric acid is one of the fundamental ingredients in the synthesis and production of PVC.
2 In the steel industry
Hydrochloric acid is used to prepare the surface of different types of steel for later use. In these cases, the acid reacts with and dissolves the superficial layer of metallic oxides, leaving a clean surface ready for further treatment, whatever this treatment may be.
3 Metal engraving
HCl can react with aluminum and other metals, oxidizing them and dissolving them as a salt (aluminum chloride, for example) while releasing hydrogen gas. This reaction can occur spontaneously at room temperature. Thanks to this, dilute solutions of hydrochloric acid can be used to corrode the surface of metals in a controlled manner, thus being able to record different patterns on its surface and give them different finishes.
4 It is used in the production of calcium chloride
We have already seen how the reaction of HCl with calcium carbonate produces calcium chloride and how this reaction is used to dissolve limescale deposits in pipes and kettles. However, calcium chloride itself is also an inorganic chemical compound of great industrial importance, being used as a stabilizer in the production of many foods and as a salt to melt ice and snow on roads.
Industrially, calcium chloride is produced by reacting limestone (mainly containing calcium carbonate bound with magnesium carbonate) with hydrochloric acid.
5 It is used in food production and processing
In the food industry, hydrochloric acid finds many uses, among which its use as a food acidulant stands out in those cases in which vinegar or citric acid are not an option. Additionally, many food products such as cookies, processed tomato sauces, and corn syrups rely on hydrochloric acid for processing.
6 In fur processing
The treatment of skins known as leather tanning is carried out to preserve the leather and to obtain a texture with different finishes. It is a complex chemical process that involves several phases. During the liquid processing of the leather, the leather is reacted with trivalent chromium ions, and this reaction requires an acid medium which is provided by hydrochloric acid.
Other industrial applications
Hydrochloric acid participates in a myriad of chemical reactions that are used in different industries.
A large number of drugs are slightly water-soluble alkaline organic compounds that are converted into soluble salts through their reaction with hydrochloric acid (this is the case of any drug or active substance that contains HCl, “hydrochloride” or “hydrochloride”) . ” as part of its name, such as lidocaine hydrochloride, for example).
In addition to this, it is also used:
- In the construction industry
- In the extraction and obtaining of lithium for the manufacture of rechargeable batteries
- In the oil industry to increase the porosity of rock in oil wells
- In the production of gelatin-based products
References
Condorchem Envitech. (2022, March 17). Extraction, crystallization and processes for obtaining lithium compounds . https://condorchem.com/es/blog/extraction-cristallization-processes-obtaining-lithium-compounds/
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In-Cosmetic Global. (2020, May 9). Tanning Industry . https://www.products.pcc.eu/es/k/industria-del-bronceado/
Mount Sinai. (nd). Hydrochloric acid poisoning . Mount Sinai Health System. https://www.mountsinai.org/health-library/poison/hydrochloric-acid-poisoning#:%7E:text=If%20the%20chemical%20is%20on,by%20a%20health%20care%20provider .
Skelly, J. (2020, August 3). Hydrochloric acid | Muriatic acid | Chemical Safety Information . ChemicalSafetyFacts.org. https://www.chemicalsafetyfacts.org/en/hydrochloric-acid/
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