Hydrohalic Acids

Hydrohalic acids are commonly termed as Hydrogen Halides when they dissolve in water to give acids. They are diatomic organic compounds with a formula HX, X represents any of the halogens. Some of the halogens include iodine, chlorine, bromide and fluorine. Among this hydrogen fluoride, chlorine and bromide fall under the category of Volcanic gasses. Hydrogen chloride forms a primary component of gastric acid when present in the form of hydrochloric acid.

Volcanic gasses consists of dissolved gasses found in lava and gasses trapped in vesicles in volcanic rocks. These gasses can be found in Earth’s Atmosphere, Earth’s Crust and Earth’s Mantle. Gastric acid is found in the stomach which is a digestive fluid that is comprised of hydrochloric acid.

Physical Properties of Hydrogen Halides.

At STP – Standard Temperature and Pressure, the hydrogen halides are colorless gas. Hydrogen Fluoride is an exception case as it boils at nineteen-degree celsius. Hydrogen Fluoride can condense under cool condition. They have an abnormal boiling point and the reason for this is that they form the hydrogen bond. Each fluorine atom comprises of three lone pairs of electrons representing highly charged recharge of space. Outer electrons are present at n=2 level. The below figure illustrates the above concept.

The concentrated hydrohalic acid produces white fumes that are caused by the small droplets of a concentrated aqueous solution of hydrohalic acid. Rest of the hydrogen halides do not form a hydrogen bond.

The Acidity of Hydrogen Halides

Let us consider the reaction of hydrogen chloride with water. Hydrogen chloride falls into a category of acid as it denotes protons to other species. When hydrochloric acid is dissolved in water it forms an hydrochloric acid. The fumes of hydrochloride are moist and this is caused when hydrogen chloride reacts with water vapor in the presence of air resulting in the cloud of concentrated hydrochloric acid.

Hydrogen Chloride denotes a proton to a lone pair of a water molecule. A dative covalent bond is formed between transferred proton and oxygen.

\(H_{2}0+HCL
ightarrow H_{3}O^{+}+Cl^{-}\)

Hydrochloric acid is the strongest acid has it fully ionizes in water.


Practise This Question

If for a function f(x), f(a) = 0, f'(a)=0, f"(a) > 0, then at x = a, f(x) is 
[MP PET 1994; Pb. CET 2002]