Strong corrosiveness and volatility: concentrated hydrochloric acid smokes in the air, and when it touches ammonia vapor, it will generate white clouds. Water absorption: it does not have water absorption. Its gas is harmful to animals and plants. Hydrochloric acid is a very strong inorganic acid, which has corrosive effect on skin or fiber, and can react with many metals to generate metal chloride and release hydrogen.

Extended data:

Use of industrial hydrochloric acid:

1, analytical chemistry

In analytical chemistry, when acid is used to determine the concentration of alkali, hydrochloric acid is generally used for titration. Titration with strong acid can make the end point more obvious, so the result is more accurate. At 1 standard atmospheric pressure, 20.2% hydrochloric acid can form an azeotropic solution, which is often used as a reference substance in quantitative analysis at a certain atmospheric pressure. Its concentration at constant boiling will change with the change of air pressure.

2. Pickled steel

One of the most important uses of hydrochloric acid is pickling steel. Before the subsequent treatment of iron or steel (extrusion, rolling, zinc plating, etc.), the rust or iron oxide on the surface can be reacted with hydrochloric acid. Hydrochloric acid solution with concentration of 18% is usually used as pickling agent to clean carbon steel.

3. Preparation of organic compounds

Another main use of hydrochloric acid is to prepare organic compounds, such as vinyl chloride, dichloroethane, bisphenol A, the precursor of polycarbonate, polyvinyl formal, ascorbic acid and so on.

Baidu Encyclopedia-Industrial Hydrochloric Acid