Interesting Facts about Hydrochloric Acid

A wide variety of industries and medical fields make use of hydrochloric acid. HCl is the simplest chlorine-based acid and has strong corrosive properties, so it is widely used in industry despite being a dangerous and destructive compound. If water components evaporate and amount to less than 60% of the total solution, the aqueous solution must be pressurised or cooled to prevent the formation of a toxic gas.

It is a clear or slightly yellowish solution with a strong, distinctive odour. In terms of acidity, it ranks among the top. Historically, HCl was made by mixing green vitriol and rock salt, and later, common salt and sulfuric acid.

It is no secret that hydrochloric acid is a powerful acid. HCl is also classified as an inorganic chemical. Since only one covalent bond connects hydrogen and chlorine in this corrosive acid, it is a simple diatomic molecule. The electronegative nature of the chlorine atom, in comparison to the electropositive nature of the hydrogen atom, causes the molecules to be attracted in the opposite direction due to the chemical bond between them.

What are the functions of hydrochloric acid?

Hydrochloric acid in your body

Hydrochloric acid is naturally produced by and has a crucial function within the human body. A lack of stomach hydrochloric acid is medically known as hypochlorhydria.

Where does stomach acid come from? Hydrochloric acid, several enzymes, and a mucus coating make up the stomach’s concealment, which keeps your food safe while you eat. The digestive process is aided by hydrochloric acid, which helps the body digest protein and other similar compounds. Additionally, it protects you from getting sick by getting rid of harmful bacteria and viruses in your stomach.

A person’s ability to digest food and absorb nutrients can be severely hampered by low levels of hydrochloric acid. Hypochlorhydria, if untreated, can lead to gastrointestinal system damage, infections, and other chronic health problems.

Hydrochloric acid can eat away at your skin, eyes, and other delicate tissues. Short-term (acute) inhalation exposure has the potential to irritate the eyes, nose, and respiratory tract, and even cause inflammation and pulmonary edoema. Humans can experience severe burns, ulcers, and scarring from skin contact, and corrosion of the mucous membranes, oesophagus, and stomach from ingestion. Hydrochloric acid has been linked to a variety of health problems in workers, including chronic bronchitis, dermatitis, and photosensitisation from prolonged skin and inhalation exposure. Even at low concentrations, prolonged exposure can discolour teeth and wear down enamel.

Hydrochloric acid in industry

Hydrochloric acid has many applications in industry. Polyvinyl chloride (PVC), bisphenol A (BPA), and ethylene dichloride (EDC) all use it as a key component in their final products (EDC). There has been a health scare about BPA, a chemical used to make polycarbonate plastics and epoxy resins, because of its carcinogenic effects. It is for this reason that many plastics are now marketed as being BPA-free. Although they are useful in the plastics industry and as laboratory solvents, all of these organic compounds have the potential to cause cancer in humans.

In leather tanneries, hydrochloric acid is typically employed during one specific step of the process. When skins are tanned, a chrome salt is introduced to alter the collagen network within. Sodium chloride and chrome salts are dissolved in a bath with a pH of 2.5–3. At this point, the pickling process begins. The next step, called basification, involves fixing the chromium to the hide, which raises the pH of the leather. Hydrogen chloride is required to get to the acidic conditions of the pickling stage.

The salt used in cooking and for consumption is sometimes “purified” with hydrochloric acid. The acidity of many solutions, such as those used in pharmaceuticals, food additives (such as fructose, citric acid, and hydrolyzed vegetable protein), and waste and drinking water, is regulated by hydrochloric acid.

Hydrochloric acid in the home

Lower amounts of hydrochloric acid, while still caustic, are safe enough to use around the house because of their excellent cleaning and pH-adjusting properties. Some people have had success using a solution of 10 parts water to one part HCl to clean the grout between tiles.

Many commercially available metal cleaning products employ the same solution because it is effective at removing stains from iron, copper, brass, and other metals. Like steel pickling, this process oxidises the surface layers to flush off stains and impurities.

HCl is a common ingredient in many highly effective household cleaners. If you happen to spill hydrochloric acid on a fragile surface, you can neutralise it by using a paste made of bicarbonate of soda and water.