Hydrochloric acid is formed when hydrogen chloride is dissolved in water.
An ion is an atom or molecule with more or fewer electrons than normal, which gives it a positive or negative electrical charge. Because an ion “desires” to become neutral by acquiring or losing additional electrons, it has interesting chemical characteristics. Ions usually come in the form of solutions. There are three types – anions, which are negatively charged, cations, which are positively charged, and radicals, or radical ions, which are highly reactive because they have a lot of free electrons.
An ionic solution is normally created when certain molecules, such as salt, are dissolved in water. Interactions between solute and solvent molecules disassociate weakly bonded molecules, such as salt, into two or more ions. When salt is placed in water, it breaks down into sodium and chloride ions, both of which are essential to human life. If a person is deprived of salt for a long time, he will eventually die. Other ions essential for life (called electrolytes) are potassium (K + ), calcium (Ca2 + ), magnesium (Mg2 + ), hydrogen phosphate (HPO42 – ) and hydrogen carbonate (HCO3- ).
Other ion solutions besides dissolved salts are acids and bases. For example, hydrochloric acid is formed when hydrogen chloride is dissolved in water. Hydrogen chloride splits into two ions, H + and Cl – . OH + reacts with water to produce H 3 O + , hydronium ion, while chlorine remains as chloride ion. As the ionization process is complete, hydrochloric acid is called a strong acid. The strength of acids is measured by how many H+ ions they have – hydrochloric acid is therefore very acidic. In fact, hydrochloric acid can dissolve through glass and all metals except iridium, although its corrosion rate is slow.
Another category of ionic solutions are bases. Instead of being measured by the concentration of hydrogen ions, a base is measured by its concentration of hydroxide ions (OH – ). An example of a base is potassium hydroxide, which is the chemical precursor of most liquid and soft soaps. When dissolved in water, potassium hydroxide produces a strong alkaline solution. An alkali is a type of base. Potassium hydroxide has a number of interesting chemical properties – one of which is its hygroscopic (water-attracting) nature, which makes it a powerful desiccant. When it reacts with water, the reaction is exothermic, which means it generates significant heat.
The last main group of ions are radical ions or just radicals. Examples of radicals include superoxide (O 2 – ), which the immune system uses to kill invading microorganisms, and nitric oxide, which the body uses as an important signaling molecule. Like acids and bases, radicals are highly reactive and have many applications in chemistry. One unfortunate aspect of radicals is that small amounts in the body tend to break down tissue over time, contributing to aging.