There is no such thing as salt-fried chicken, only hydrochloric acid.

Hydrochloric acid is an aqueous solution of hydrogen chloride (English: hydrochloric acid; chemical formula: HCl). Its scientific name is hydrochloric acid. It is a monovalent inorganic strong acid and has a wide range of industrial uses. Hydrochloric acid is a colorless and transparent liquid with a strong pungent odor and high corrosiveness. Concentrated hydrochloric acid (mass fraction is about 37) is extremely volatile, so when the container containing concentrated hydrochloric acid is opened, the hydrogen chloride gas will volatilize and combine with water vapor in the air to produce small droplets of hydrochloric acid, causing acid mist to appear above the bottle mouth. . Hydrochloric acid is the main component of gastric acid, which can promote food digestion and resist microbial infections.

In the 16th century, Libaphius officially recorded the preparation method of pure hydrochloric acid: mixing concentrated sulfuric acid and table salt and heating it required a round-bottomed flask, an alcohol lamp, an asbestos mesh and an iron stand. Preheat and heat evenly. If you use an alcohol lamp to heat slightly, you will get sodium bisulfate and hydrogen chloride. If you use an alcohol burner to increase the heating, you will get sodium sulfate and hydrogen chloride. Pure hydrochloric acid can be obtained by absorbing hydrogen chloride with water. Note that the catheter cannot be inserted directly into the water, but a funnel must be connected. Because hydrogen chloride is easily soluble in water, the pressure in the catheter will decrease and the water will flow back into the flask and float on the flask. The heat generated above concentrated sulfuric acid will cause the water to boil, causing sulfuric acid droplets to splash around, causing accidents. If a funnel is connected, when the hydrogen chloride is discharged, the contact area with water is large and it is fully dissolved in the water. The pressure in the funnel decreases and the liquid level rises. The liquid level in the beaker will drop. When the liquid level is about to leave the funnel mouth, The liquid in the funnel will fall due to gravity and will not flow back into the flask. Later, chemists such as Glauber, Priestley, and David also used hydrochloric acid in their research.

During the Industrial Revolution, hydrochloric acid began to be mass-produced. In the chemical industry, hydrochloric acid has many important applications and plays a decisive role in the quality of the product. Hydrochloric acid can be used to pickle steel and is also a chemical reagent required for the large-scale preparation of many inorganic and organic compounds, such as vinyl chloride, the precursor of PVC plastic. Hydrochloric acid also has many small-scale uses, such as household cleaning, production of gelatin and other food additives, descaling agents, and leather processing. Approximately 20 million tons of hydrochloric acid are produced globally every year.

Hydrochloric acid is a colorless liquid (industrial hydrochloric acid will be slightly yellow due to the presence of impurity ferric salts). It is an aqueous solution of hydrogen chloride and has a pungent smell. The hydrochloric acid used in general laboratories is 0.1 mol/ L, pH=1. Because concentrated hydrochloric acid is volatile, the volatile hydrogen chloride gas reacts with water vapor in the air to form small droplets of hydrochloric acid, so you will see white mist. Hydrochloric acid is arbitrarily miscible with water and ethanol. Concentrated hydrochloric acid releases heat when diluted. Hydrogen chloride can be dissolved in benzene.

Hydrochloric acid is a strong monobasic acid, which means it can only dissociate into one hydrogen ion. The hydrogen chloride molecules in the aqueous solution are completely ionized, and the ionized hydrogen ions complex with a water molecule to become hydronium ions, making the aqueous solution acidic.

The anion generated after ionization is chloride ion, so hydrochloric acid can be used to prepare chlorides, such as sodium chloride.

When hydrochloric acid is dissolved in alkali solution, a neutralization reaction occurs with the alkali solution. For example: hydrochloric acid can neutralize the acid and base of sodium hydroxide to produce table salt:

Dilute hydrochloric acid can dissolve many active metals (metal activity ranks before hydrogen), producing hydrochloric acid salts and hydrogen gas.

Metals whose activity order is after hydrogen, such as copper, mercury, silver, platinum, and gold, cannot react with dilute hydrochloric acid.

Hydrochloric acid, sulfuric acid and nitric acid are collectively known as the three strongest industrial acids. In addition, hydrobromic acid and hydroiodic acid are also strong acids, and perchloric acid is the strongest acid.

Hydrochloric acid has reducing properties and can react with some strong oxidants to release chlorine gas. In the laboratory, manganese dioxide is used to oxidize concentrated hydrochloric acid to prepare chlorine gas.

Some oxidizing bases and hydrochloric acid can undergo redox reactions instead of simple neutralization reactions.

Hydrochloric acid can perform nucleophilic substitution on alcohols to generate halogenated hydrocarbons.

Hydrogen chloride can also add olefinic double bonds to obtain chlorinated hydrocarbons.

Amines are usually not very soluble in water, but can be dissolved in dilute hydrochloric acid to form ammonium salts. For example: aniline dissolves in hydrochloric acid to form anilinium chloride.

The hydrochloride of amine is an ionic compound. According to the principle of similar miscibility, it has a large solubility in water. Ammonium salts can turn back into amines when exposed to strong bases.

Using such properties, amines can be separated from other organic compounds.

In addition, the melting point or decomposition point of the amine hydrochloride can be used to determine the type of amine.

Zinc amalgam can be produced by reacting zinc particles with mercury chloride in dilute hydrochloric acid. The latter can be refluxed with concentrated hydrochloric acid, aldehydes or ketones to reduce the carbonyl groups of aldehydes and ketones to methylene groups, which is Clemson reduction reaction.

However, it should be noted that this method is only applicable to compounds that are stable to acids. If there are α, β-carbon-carbon double bonds, etc., they will also be reduced:

Anhydrous zinc chloride Lucas reagent can be prepared by dissolving in high-concentration hydrochloric acid, which can be used to identify whether alcohols with six carbon atoms and below are primary, secondary or tertiary alcohols. The Lucas reagent is immediately turbid with tertiary alcohol, turbid with secondary alcohol for 2-5 minutes, and turbid with primary alcohol.

I hope I can help you clear up your doubts.