Hydrochloric acid formula properties uses with examples.
Hydrochloric acid is also known as hydrogen chloride, is a chemical compound of hydrogen and chlorine with molecular formula, HCl.
About 42% of HCl [ in stoichimetric ratio] or concentrated aqueous solution of hydrogen chloride gas at S.T.P, is known as hydrochloric acid.
The another name of hydrochloric acid are chlorane, muriaticacid, spirits of salt, chlorhydric acid etc.
Hydrochloric acid formula
Hydrochloric acid is a diatomic molecule with chemical formula, HCl.
Hydrochloric acid is the salt of hydronium ion( H3O+) and chloride ion. It is produced when HCl is dissolved in water.
The structure of bulk water is infamously complex. Infra red spectroscopy, X-ray and neutron diffraction study of conc.HCl acid solutions revealed that the primary form of H+(aq) in these is H 5O 2+.
This form along with chloride anion, is H-bonded to the neighboring water molecules in several different ways.
In is sandwiched midway between two water molecules at 180 ᵒ . The simple chemical formula and Lewis dot structure of hydrochloric acid molecule are shown below.
Hydrochloric acid properties
There are two type of properties of hydrochloric acid in chemistry, namely physical properties and chemical properties.
Most the of the important properties of hydrochloric acid are discussed below with example.
Hydrochloric acid physical properties
is an anti-breathing, Hydrogen chloride colorless gas with pungent smell. It is a polar covalent compound of hydrogen and chlorine elements. The dipole moment of H-Cl acid is 1.03 D.
In ordinary temperature, HCl is a gas. But it is easily compressed to colorless liquid and also to white crystalline solid under low temperature and high pressure.
Although, hydrochloric acid is a covalent hydride of hydrogen yet it has more ionic character due to high electronegativity of chlorine atom.
Hydrogen chloride is a gas at room temperature. But it is easily compressed to colorless liquid and also to white crystalline solid under high temperature and low pressure.
HCl gas is slightly heavier than air. When HCl gas come in contact with aquatic air it creates white smoke.
Melting and boiling point of hydrochloric acid
T he melting point and boiling point of hydrochloric acid are, 159 K and 189 K respectively. Because, at ordinary temperature, HCl is a gas.
That is, HCl molecules remain as an individual molecule. Hence, HCl is a gas at room temperature.
Consequently, t he melting point and boiling point of hydrochloric acid is less than HBr andHI acids.
Chlorine is a strong electronegative element than hydrogen. So, H-Cl bond is more polar and more strong thanH-Br and H-I bond.
Hence, the bond dissociation energy of H-Cl bond is higher than that of H-Br and H-I bond. The bond dissociation of H-Cl bond is 432 KJ/mole.
Therefore, H — Cl is more stable compound than HBr and HI molecules.
Hydrochloric acid density
Hydrogen chloride gas is super soluble in water, when dissolved.
At 273 K temperature and one atmosphere pressure, about 42% of HCl [ in stoichimetric ratio] or concentrated aqueous solution of hydrogen chloride gas is known as hydrochloric acid.
The 100 ml concentrated hydrochloric acid solution contains 39 ml of HCl. The density of hydrochloric acid is1.2 g/ml or 1200 g/litre.
It is a strong mono basic weak acid. The pKa value of HCl acid is, -7.
Hydrochloric acid laboratory preparation
Hydrogen chloride is prepared in the laboratory by heating of a mixture of sodium chloride and concentrated sulfuric acid.
The reactions consist of two step. In the first step, sodium chloride react with concentrated sulfuric acid at low temperature [ 420K ], giving NaHSO4 and HCl.
In the second step,the rest of the NaCl reacts with the producing sodium hydrogen sulfate at high temperature [ 823K ] and produce the expected hydrogen chloride gas.
The producing hydrogen chloride gas is dried on passing through theconcentrated sulfuric acid.
Industrial method for preparation of hydrogen chloride
When equal volume of hydrogen and chlorine is passed through a tube into a combustion cell which is made by silica, then HCl gas is obtained.
The producing hydrogen chloride gas is passing through a cold cell for cooling.
After cooling, the HCl gas is added to water through which the expected hydrochloric acid is obtained. This is the large scale preparation method of HCl acid in the world.
Hydrochloric acid chemical properties
Since the bond dissociation energy of H-Cl bond is higher than H-Br and H-I bond, hence hydrochloric acid is a mild reducing agents.
But some oxidizing agent, such as, KMnO4, K2Cr2O7,Pb3O4 and PbO 2 etcoxidize hydrochloric acid to release chlorine gas.
Thermal stability of HCl
The bond dissociation of H — Cl bond is 103 Kcal/mole, which is higher than that of HBr and HI.
So, the H — Cl bond does not dissociate easily. Hence, HCl is thermally more stable than HBr and HI.
Hydrochloric acid strength explanation
HCl gas is highly soluble in water. When HCl gas is dissolved in water, the resulting aqueous solution is called hydrochloric acid. The aqueous solution produce H 3 O+ and Cl- ions.
So, HCl acid is a strong acid The aqueous solution of HCl change the litmus paper color from blue to red.
Hydrochloric acid is also reacts with metallic carbonate or bicarbonate, and evolved a effervescence colorless, odorless CO2 gas.
Besides, hydrochloric acid reacts with metal oxide and hydroxide to form salt and water. The above reaction proved that HCl is a strong acid.
Although, HCl is a stronger acid than HF but it is a weaker acid than HBr or HI.
Hydrochloric acid uses in chemistry
There are a large number of application of hydrochloric acid as an important chemical in chemistry. HCl acid play an important role both in organic and in inorganic chemistry.
HCl has a great significant in industrial production of different goods.Some important uses of hydrochloric acid is discussed below.
Hydrochloric acid use as an important laboratory reagent
Hydrochloric acid is used as an important laboratory reagent. It is used as a reducing agent, catalytic reagent, hydrolyzing agent, in the preparation and identification of many organic compounds.
Anhydrous ZnCl2 and concentrated HCl mixture which is known as Luis reagent, is used for identification of primary, secondary and tertiary aliphatic alcohol.
Hydrochloric acid is also used in industrial production of some important substance, such as metal chloride, chlorine, ammonium chloride and production of glucose from starch.
Again, in galvanization process, HCl is used as a cleaning substance. It is used to clean iron sheet before tin plating or galvanization. That is, for removal of iron oxide layer from the surface of iron sheet.
Most important use of HCl acid is in the dyeingindustry, in the medicine production industry and in sugar industry.
Hydrochloric acid use as a strong oxidizing agent
Although HCl acid is a mild reducing agent yet it can use as oxidizing agent with nitric acid.
Actually, in this case the mixture of concentrated HCl and HNO 3 produce nascent chlorine atom which act as a oxidizing agent and oxidize ‘Au’ to AuCl 3.
Hydrochloric acid is used to prepare of chlorine
The chemical process, in which HCl gas is oxidized by air oxygen in presence of CuCl 2 catalyst to form chlorine, is known as Deacon’s process.
There are some metals, which are electro-positive than hydrogen, react with dilute HCl and produced hydrogen gas. For example, zinc, magnesium, iron, calcium etc.
Beside the above uses, HCl is used in industry for removal of lubricants from animal bone and also use for its purification.
Details of hydrochloric acid in chemistry
Hydrochloric acid formula
Hydrochloric acid properties
Melting and boiling point of hydrochloric acid
Hydrochloric acid density
Hydrochloric acid preparation
Hydrochloric acid strength explanation
Hydrochloric acid uses in chemistry
Originally published at https://chemizi.blogspot.com.
