Concentrated hydrochloric acid is used in pharmaceutical analysis; diluted is used for therapeutic purposes. The State Pharmacopoeia has special tables with which you can determine the percentage of acid in an aqueous solution. To do this, you only need to know its specific gravity.
Using these tables, you can quite simply check the concentration of this acid solution. Conventional (insufficiently accurate) acid solutions can be prepared quickly using common methods. For example, there is hydrochloric acid with a specific gravity of 1.19, that is, containing 37% HC1. Suppose you want to prepare 100 milliliters of 10% acid. For this, an appropriate proportion should be made: in every 100 parts by weight of HC1 available, 37 parts of hydrogen chloride are contained. Since we need to prepare a 10% solution, it should contain ten parts by weight in a hundred parts of the solution.
Therefore, in this case, X is a value that will indicate how many weight parts of a 37 percent solution should be taken so that, diluting them with water to 100 weight parts, a 10% solution is obtained:
100-37
X-10
X = 100 * 10/37 = 27 parts by weight.
Hydrogen chloride is a fairly toxic substance that can cause serious burns, as well as intoxication of the whole body. Burnt magnesia is used as an antidote for HC1 poisoning. To neutralize the acid, you can also use soapy water, pulverized animal charcoal, milk, various enveloping substances.
When intoxicated with acids through the mouth, you can not prescribe emetics, and also use inside preparations containing carbonic alkali. In case of poisoning, the stomach is washed with plenty of water using a probe. Good results are obtained when magnesium impurities are added to water. In the presence of external burns with acids, doctors recommend rinsing the lesion site for a long time with water. The burn area and its circumference are cleaned with pure ethanol, after which a slurry of bicarbonate of soda is applied, and on top of all this - 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.
HC1 is obtained in the main chemical industry from hydrogen chloride gas absorbed by water. Hydrogen chloride is obtained by the interaction of sulfuric acid with sodium chloride.
Cleanliness test
There are some requirements:
- hydrochloric acid in its composition should not contain salts of heavy metals, nitric, nitrous and sulfurous acids, free chlorine and arsenic;
- only insignificant traces of iron salts are allowed, impurities of free C1 can be discovered by the reaction: C12 + 2K1-2KS1 + 12;
- to determine the impurities of sulphurous acid, a solution of iodine in potassium iodide is prepared with an indicator - a starch solution, the blue color of the solution in the presence of sulphurous acid decolours for 30 seconds
- a significant residue upon evaporation of 10 grams of acid should not exceed 0.01 percent (mineral impurities).
Quantitative analysis is carried out by titration of a solution of sodium hydroxide in the presence of a methyl orange indicator. The content of HC1 in the acid is 24.8-25.2%.
Hydrochloric acid is a part of biological fluids. For example, in the gastric juice its concentration is up to 0.5%, it helps the breakdown of proteins. Diluted HC1 (8.2%), when administered orally, activates the conversion of pepsinogen (proenzyme) to pepsin, enhances the secretory activity of the pancreas, and promotes the movement of stomach contents into the intestines. It has an antibacterial effect in relation to the vegetative and spore microflora. This acid is prescribed orally with reduced acidity, for iron absorption in the treatment of anemia.