7647-01-0

The IUPAC name of Hydrochloric acid is chlorane. With the CAS registry number 7647-01-0 and EINECS 231-595-7, it is also named as Acide chlorhydrique. Hydrochloric acid is a clear, colourless solution of hydrogen chloride (HCl) in water. It is a highly corrosive, strong mineral acid with many industrial uses. Hydrochloric acid is found naturally in gastric acid.It is liquefied to colorless liquid at -85 °C. At -112 °C, it becames white crystal.

Physical properties about Hydrochloric acid are: (1)Enthalpy of Vaporization: 16.15 kJ/mol; (2)Boiling Point: -84.899 °C at 760 mmHg; (3)Vapour Pressure: 33917.87890625 mmHg at 25°C.

Preparation of Hydrochloric acid: It is obtained from four major methods:
1. It can be produced as a by-product in the chlorination of both aromatic and aliphatic hydrocarbons or from the thermal degradation of organic chlorine compounds, CH₄ + Cl₂ → CH₃Cl + HCl  CH₂ClCH₂Cl → CH₂=CHCl + HCl
2. It can be obtained from the reaction of sodium chloride (salt) and sulfuric acid, 2NaCl + H₂SO₄ → Na₂SO₄ + 2HCl
3. It also can be prepared from the combustion of hydrogen and chlorine, C1₂ + H₂ → 2HCl
4. It can be obtained by Hargreaves-type operations, 4NaCl + 2SO₂ + O₂ + 2H₂O → 2Na₂SO₄ + 4HCl

The reaction between hydrogen and chlorine is highly exothermic and spontaneously goes to completion as soon as it is initiated. The equilibrium mixture contains about 4% by volume free chlorine. As the gases are cooled, the free chlorine and free hydrogen combine rapidly so that when 200 °C it is reached, the gas is almost pure hydrogen chloride. By carefully controlling the operating conditions, a gas containing 99% hydrogen chloride can be produced and it can be further purified by absorbing it in water in a tantalum or impervious or impregnated graphite absorber. The aqueous solution is stripped of hydrogen chloride under slight pressure, givimg strong gaseous hydrogen chloride that is dehydrated to 99.5% hydrogen chloride by cooling it to -12 °C.

Uses of Hydrochloric acid: It may be used to treat cotton to delint it, and to separate it from wool. In the semiconductor industry, it is used to both etch semiconductor crystals and to purify silicon via SiHCl₃. It is also an important reagent in other industrial chemical transformations, e.g.: Hydrochlorination of rubber; Production of vinyl and alkyl chlorides. Large amounts of anhydrous hydrogen chloride are needed for preparing methyl chloride, ethyl chloride, vinyl chloride, and other such compounds. It is replacing sulfuric acid in some applications such as metal pickling, which is the cleaning of metal surfaces by acid etching. It leaves a cleaner surface than sulfuric acid, reacts more slowly, and can be recycled more easily. It is used in chemical manufacture especially for phenol and certain dyes and plastics. In oil well drilling, it increases the permeability of limestone by acidifying the drilling process.

When you are using this chemical, please be cautious about it as the following:
It is extremely flammable, can cause burns and may form explosive peroxides, so people should keep it away from sources of ignition. It is not only harmful by inhalation and if swallowed, but also irritating to eyes, respiratory system and skin. It also has limited evidence of a carcinogenic effect. Repeated exposure may cause skin dryness or cracking. What's more, vapours may cause drowsiness and dizziness. In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. When using it, people should take precautionary measures against static discharges. If you want to contact this product, you must wear suitable protective clothing, gloves and eye/face protection. In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) If swallowed, seek medical advice immediately and show this container or label.

You can still convert the following datas into molecular structure:
1. SMILES:Cl
2. InChI:InChI=1/ClH/h1H
3. InChIKey:VEXZGXHMUGYJMC-UHFFFAOYAT

The toxicity data is as follows: