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Unacademy presents a bird’s eye view of the main Chemistry topics for all IIT-JEE aspirants. Hence, whether it is a quick revision or a detailed conceptual study, our professional teachers make things easy and effective for hardworking students. So, today, Unacademy brings to you some detailed but crisp notes on hydrochloric acid.
It is a strong corrosive acid that contains one atom of hydrogen and one atom of chlorine. Hence, it is a simple diatomic molecule and is an inorganic chemical. It is well-known for its characteristic pungent smell. Let us know more about it in detail.
Structure:
This acid is a simple diatomic molecule, having one hydrogen atom (H+) and one chlorine atom (Cl-). It is connected with a single covalent bond. The covalent bond formed is a polar bond because the electronegativity of the chlorine is greater than that of the hydrogen atom.
Preparation:
The simple process to make hydrochloric acid is to dissolve hydrochloride in water. The water molecules get attached to the hydrogen atom in the hydrochloride and separate it away from the chlorine ion. The hydrogen chloride gas then enters the water and the acid is formed. The process is called dissociation reaction and hydrogen chloride is also formed as the byproduct of this reaction. When this acid needs to be prepared at an industrial scale, combustion of chlorine and hydrogen is done. It results in dilute hydrochloric acid and hence another process is required to obtain it in concentrated forms. To achieve so, direct combustion of chlorine and hydrogen is made using the synthetic method to gain large concentrations of this acid commercially.
Physical properties:
Hydrochloric acid doesn’t have any color or can be termed colorless. It has a highly pungent odor. The boiling point and melting point of this acid depend on its concentration. It starts fuming if present in concentration form. It appears to be a transparent liquid.
Further, it should be stored in a cool, dry, and moisture-free area that is fully ventilated. It should never be stored in organic materials, metals, and oxidizing agents. It should be placed in a tight glass container in a safe place to avoid accidental contact.
Chemical properties:
It is a strong acid and is highly corrosive to metals like gold, silver, platinum, tantalum, mercury, etc. It can perfectly dissolve metals and can form oxidized metal chlorides with the release of hydrogen gas. Its molecular weight is 36.458 g/mol.
It is a monoprotic acid, i.e., it can release a single proton only. When dissolved in water, it completely dissociates into hydrogen and chloride ions. This is because it is a covalent compound and ionizes completely when added to water.
It is used as dilute hydrochloric acid or in concentrated forms depending on the type of reaction. Hence, all major reactions of this acid contain common strong acids. These include reactions containing weak acid salts in which displacement of heavy acid takes place, reactions containing hydroxide and metal oxides which become neutral and form metal chloride and water, and metal reactions involving displacement of hydrogen gas, etc.
Uses:
There are multiple uses of concentrated or dilute hydrochloric acid. Some of the top uses include:
- It is used in the purification of table salts and regulation of the acidity of solutions.
- It is used to control the pH of pharmaceutical products, foods, and water.
- It is used in oil production and is used on the rocks to form large pore-like structures.
- It is a perfect cleaning agent for eliminating rust or stains from copper, iron, etc. Hence, it is used widely at homes and commercial establishments.
- It is used in the pickling of steel.
- It is used to produce many organic and inorganic compounds.
- It forms a part of the gastric juices in the human body and is also called gastric acid.
Hazards:
The corrosiveness of hydrochloric acid makes it a hazardous chemical to deal with. The concentration form of this acid releases acidic mist and fumes. A small amount of inhaling this acid results in eyes, nose, and respiratory tract irritations. Oral contact with this acid damages mucus membranes, stomach, and other internal body parts. If a person is having continuous exposure to this acid, it may result in gastritis, chronic bronchitis, etc.
If inhalation of the vapors of this acid takes place, it is important to go into the fresh air. The person should inhale and exhale aggressively and call for medical attention as quickly as possible.
If this acid is ingested by mistake, vomiting should never be induced. The person who has ingested the acid should be taken to the medical care professional quickly.
If this acid gets in contact with the eyes, immediately wash them for at least fifteen minutes. Once done, it is important to see a medical professional.
If this acid gets in contact with skin, it should be properly flushed with water for at least 15 minutes. Any contaminated clothing should be immediately removed and antibacterial or disinfectant soaps can be immediately applied to the area. Further, it is crucial to go and get professional medical help.
How to handle hydrochloric acid?
Many laboratories prefer to work with dilute hydrochloric only due to its hazardous nature. However, safety standards are necessary while dealing with this corrosive acid. While dealing with it, the following safety equipment can be of high use:
- Face shield,
- Boots,
- Vapor respirator,
- Rubber gloves,
- Full suit, etc.
Not only this, there should be clear access to the eye flush station to avoid any long-time contact of this acid with the eyes. While using this acid at home, it is important to handle it by following the instructions and guidelines to use only. Many times, it is recommended to dilute the acid before starting to use it.
Conclusion:
Hydrochloric acid is formed by the single covalent polar bond between one hydrogen and one chlorine atom. It is a colorless liquid with a strong and pungent smell. It is highly corrosive in nature and quickly reacts with numerous metals and oxides. Hence, proper care should be taken while dealing with this acid.
Further, it can be prepared at a small scale and commercially according to the requirements by different methods. Its chemical properties reveal that it is highly reactive and hence needs to be stored properly. The detailed guidelines ensure that it is handled properly while staying prepared for all the possible hazards associated with its use.
