Hydrochloric acid: physical and chemical properties, production and use

Concentrated hydrochloric acid is used in pharmaceutical analysis, for therapeutic purposes diluted. In the State Pharmacopoeia, there are special tables with which you can determine the percentage of acid in the aqueous solution. To do this, you only need to know its specific gravity.

Using these tables, it is quite easy to check the concentration of this acid solution. Conventional (insufficiently accurate) solutions of acid can be quickly prepared using common methods. For example, there is hydrochloric acid with a specific gravity of 1.19, that is, containing 37% HC1. Assume that you need to prepare 100 milliliters of 10% acid. To do this, the appropriate proportion should be made: in every 100 parts by weight of the existing HC1 contains 37 parts of hydrogen chloride. Since we need to prepare a 10% solution, it must contain ten parts by weight in a hundred parts of the solution.

Therefore, in this case, X is a quantity that will indicate how many weight parts of 37 percent solution should be taken to dilute them with water to 100 parts by weight to obtain a 10% solution:

100-37

X-10

X = 100 * 10/37 = 27 parts by weight.

Hydrogen chloride is a fairly toxic substance that can cause severe burns, as well as intoxication of the whole organism. As an antidote for the poisoning of HC1, burnt magnesia is used. To neutralize the acid can also be used and soapy water, sprayed animal charcoal, milk, a variety of enveloping agents.

When acid intoxication through the mouth can not be prescribed emetics, as well as ingest drugs containing carbonic acid. When poisoning, the stomach is washed with a large amount of water using a probe. Good results are obtained by adding to the water an impurity of magnesium oxide. In the presence of external burns with acids, doctors recommend the place of the lesion for a long time to rinse with water. The area of the burn and its circumference is cleaned with pure ethanol, after which a gruel is placed from bicarbonate soda, and on top of this is an alcohol gauze napkin.

Hydrogen chloride is highly soluble in water. At 0 ͦ C, one volume of water dissolves five hundred volumes of gas. In medicine, industry and even in the national economy, hydrochloric acid is very often used. Its formula is represented by hydrogen and halogen-C1.

The HCl is produced in the main chemical industry from hydrogen chloride gas absorbed by water. Hydrochloric acid is obtained by the reaction of sulfuric acid with common salt.

The purity test

There are some requirements:

- hydrochloric acid in its composition should not contain salts of heavy metals, nitrogen, nitrogenous and sulfuric acids, free chlorine and arsenic;

- only insignificant traces of iron salts are allowed, impurities of free C1 can be discovered by the reaction: С12 + 2К1-2КС1 + 12;

- To determine the impurities of sulfuric acid, a solution of iodine in potassium iodide is prepared with an indicator - a solution of starch, the blue color of the solution in the presence of sulfuric acid discolored within 30 seconds

- a significant residue when evaporating 10 grams of acid should not exceed 0.01 percent (mineral impurity).

The quantitative analysis is carried out by titrating a solution of caustic sodium in the presence of an indicator of methyl orange. The content of HC1 in acid is allowed to be 24.8-25.2%.

Hydrochloric acid is also a part of biological fluids. For example, in gastric juice, its concentration is up to 0.5%, it helps the breakdown of proteins. Diluted HC1 (8.2%) when administered internally activates the conversion of pepsinogen (proenzyme) into pepsin, enhances the secretory activity of the pancreas, facilitates the movement of stomach contents into the intestine. Has an antibacterial effect in relation to the vegetative and spore microflora. This acid is administered internally with reduced acidity, for absorption of iron in the treatment of anemia.