Application
Human use:
Humans and other animals have special glands in the stomach lining that turn ingested table salt into hydrochloric acid. It can keep the gastric juice at the most suitable pH value required to activate pepsin, it can also denature the protein in the food for easy hydrolysis, and kill the bacteria that enter the stomach with the food.
Daily use:
Prepare toilet cleaners, rust removers and other daily necessities.
Industrial applications
Hydrometallurgy for rare metals
Organic Synthesis
For example, at a temperature of 180°C to 200°C and a mercury salt (such as HgCl2) as a catalyst, hydrogen chloride and acetylene undergo an addition reaction to form vinyl chloride, which is then polymerized into polyvinyl chloride under the action of an initiator. .
Dyeing industry
The pickling of cotton cloth after bleaching and the neutralization of residual alkali after cotton cloth mercerizing should use hydrochloric acid. In the printing and dyeing process, some dyes are insoluble in water and need to be treated with hydrochloric acid to make soluble hydrochloride before they can be used.
metal processing
For the pre-plating treatment of steel parts, first wash with caustic soda solution to remove oil stains, and then soak in hydrochloric acid; before metal welding, it is necessary to apply a little hydrochloric acid on the weld, etc., all of which use the property of hydrochloric acid to dissolve metal oxides , to remove rust. In this way, the metal surface can be plated firmly and welded firmly.
food industry
Hydrochloric acid is used to hydrolyze starch to make starch syrup. The preparation method is: add water to refined starch to form starch milk, add hydrochloric acid to make it acidic starch milk with a pH value of 1.9~2.1, heat and boil to hydrolyze the starch, add 5% sodium carbonate for neutralization after hydrolysis, and then filter, decolorize, Concentrate to get starch syrup.
Production of inorganic and organic pharmaceuticals
Hydrochloric acid is a strong acid that can react with certain metals, metal oxides, metal hydroxides and most metal salts (such as carbonates, sulfites, etc.) to form hydrochloride. Therefore, hydrochloric acid is used in the production of many inorganic drugs.
Many organic drugs in medicine, such as novocaine, thiamine hydrochloride (preparation of vitamin B1), etc., are also made of hydrochloric acid.
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