Hydrochloric acid
Hydrochloric acid (hydrogen chloride).
Molecular formula : HCL
(Cl = 97,23 %, H = 2,76 %)

Molar mass = 36,461 ± 0,002 g·mol-1

Formerly called "spirit of salt" or muriatic acid. This acid is a colorless liquid with a pungent odor. Concentrate can have a pH less than 1, and very corrosive.
Pure hydrochloric acid does not exist on Earth in natural state. However, this is a chemical species that has been frequently used in history from the beginnings of chemistry (using salts in presence of sulfuric acid, Jabir Ibn Hayyan Persian alchemist discovered hydrochloric acid from sodium chloride, about the year 800).
Note : HCl is the major component of gastric acid. It is present in the stomach where it helps the digestion of food.

Reacting the Cl2 chlorine gas which reacts with slight excess of H2 dihydrogen, to produce hydrogen chloride gas HCl (the reaction takes place in a burner, to 2000 ° C).

Cl2 + H2 >>> 2 HCl gas

Then the latter is absorbed in water:

HCL + water >>> HCl aqueous

Other methods based on same principle of "burning" of carbon (coke) and sulfur dioxide in presence of chlorine and water vapor:

C + 2Cl2 + 2H2O >>> 4 HCl + CO2

SO2 + Cl2 + 2H2O + >>> 2 HCl + H2SO4

Reaction between H2SO4 (sulfuric acid) and chloride Cl:
(2-step reaction with salt containing chloride [mCl])

H2SO4 + mCl >>> mHSO4 + HCl

mHSO4 + mCl >>> m2SO4 + HCl

The first reaction takes place at 150 to 300° C, while second stage requires a temperature of about 550 to 600° C and excess salt.
The Mannheim and Berlin process using this synthetic route.

Main features:
The physical properties of hydrochloric acid, such as boiling point or melting, depend on the concentration (or molar aqueous HCl solution). They since the physical properties of water varies from 0% HCl to those of fuming hydrochloric acid for higher fractions of 40% HCl.

The reference temperature and pressure for the above table are 20 °C and 1 atmosphere (101.325 kPa).

Technical solutions :

In water treatment, it is used in the injection water as dilute commercial solutions.

A formulation for the water treatment.
Reaction mechanism of calcium bicarbonates (simplified equations):

..........................2 HCl + Ca[HCO3]2 ...>>> ....2 CO2 ...+ ...2H2O + CaCl2
.......................73.......162 ou 10°............. .(2x44=88) ........................111

With 1 mg as HCl added, there has (10/73) = 0.137°F for lower TAC, and 1.205 mg as free CO2 and (71/73)= 0.97 mg/L as Cl chloride formed.

Tightly closed and dry in a well ventilated area.
For current storage: no metal containers.



Sources : personal and Wikipedia, the free encyclopedia.

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