Hydrochloric acid is a strong acid that contains a hydrogen and a chlorine atom per molecule. It is an important acid commercially and biologically, and this lesson will discuss the properties of HCl that contribute to these uses.
Acids are inorganic molecules that release hydrogen ions (positively charged hydrogen atoms) when added to water. These molecules tend to break apart (or dissociate) when added to water, and the number of hydrogen ions released during this process will determine the acidity of the solution. Acids come in two basic types: weak acids and strong acids. Weak acids dissociate partially, while strong acids dissociate completely in water. One of the most notable strong acids is hydrochloric acid (HCl or hydrogen chloride).
Let’s discuss HCl and its properties as a strong acid.
Chemical Properties of HCl
Hydrochloric acid is a strong acid and is made of hydrogen and chlorine atoms. Hydrogen and chlorine atoms participate in covalent bonding, which means that hydrogen will share a pair of electrons with chlorine. This covalent bond is present until water is added to HCl.
Once added to water, HCl will separate into hydrogen ions (which are positive and will attach to water molecules) and chloride ions (which are negative).HCl is clear and colorless when added to water. However, hydrochloric acid has a strong odor and contains a sour taste, which is typical of many acids. Hydrochloric acid dissolves in water readily at all concentrations and has a boiling point of approximately 110 degrees Celsius.
Hydrochloric acid is corrosive, meaning it will break down and erode biological tissues upon contact. Furthermore, HCl can cause massive damage internally if it is inhaled or swallowed. For these reasons, it is suggested that individuals handling HCl use gloves, goggles, and masks when working with this acid.
Commercial and Biological Uses of HCl
HCl is used in many different commercial processes.
For example, HCl is used for the production of batteries, which can be used to provide electrical energy for machinery. HCl is also used in the production of many pharmaceutical medications. For example, many medications used to treat high blood pressure contain HCl as part of the active ingredients, and this is a widespread practice amongst drug companies. HCl can also be used in the production of metals, such as steel, where it is used in the pickling (purification) of the final product.In the human body, HCl is important for the breakdown of food in the stomach. In the stomach, parietal cells produce HCl for two major reasons.
First, HCl will kill bacteria and microorganisms that can cause illness in the gastrointestinal system. This is a form of innate immunity, or immunity that is present at birth. Secondly, HCl is used by the stomach to activate enzymes that break down proteins. Chymotrypsin and pepsin are two of these enzymes, and the presence of HCl will allow these enzymes to become active and speed up the digestion process.
HCl is a strong acid, and dissociates completely in water.
It is formed by covalent bonds between hydrogen and chloride ions. HCl has many commercial uses, including use in the production of steel and in the production of medications. Additionally, the human body uses HCl for digestion by activating enzymes necessary for breaking down proteins.