In the theory of acid-base ionization, alkali refers to a substance in which all anions ionized in aqueous solution are OH-; In acid-base proton theory, alkali refers to a substance that can accept protons; In the theory of acid-base electrons, alkali refers to the electron donor.
Alkali is extremely corrosive, and its solution or dust splashes on the skin, especially on the mucosa, which can produce soft scabs and penetrate into deep tissues. There is a scar after the burn. Splash into the eye will not only damage the cornea, but also damage the deep tissue of the eye.
If it is accidentally splashed on the skin, immediately rinse it with clean water10 min; If it spills into eyes, it should be washed immediately with clear water or normal saline for 65438 05 minutes, and then 2% novocaine should be added. Severe cases are sent to hospital for treatment.
The chemical property of alkali is ***5, which is also called the universality of alkali. It should be noted that some properties are only applicable to soluble bases. Compound alkali can replace sodium hydroxide (caustic soda) and industrial soda ash (sodium carbonate). Its advantage is that the price is much cheaper than caustic soda and soda ash, and the cost performance is higher.
Ordinary alkali:
1, sodium hydroxide NaOH commonly known as caustic soda, caustic soda, caustic soda. Sodium hydroxide is widely used. In chemical experiments, it can be used not only as a reagent, but also as an alkaline desiccant, because it has strong water absorption. Caustic soda is widely used in the national economy, and many industrial departments need it.
The most used sector is chemical manufacturing, followed by oil refining, paper making, aluminum smelting, tungsten smelting, rayon, rayon and soap manufacturing.
2. Calcium hydroxide Ca(OH)2, commonly known as clarified lime water and hydrated lime, can be prepared by the reaction of quicklime (namely calcium oxide) with water, which will release a lot of heat during the reaction. Calcium hydroxide is often used in agriculture to neutralize acidic soil, and it is also used to prepare pesticide Bordeaux mixture. The main component of concrete and lime slurry in daily life is hydrated lime.
In addition, the transparent aqueous solution of calcium hydroxide is often used to test carbon dioxide in the laboratory. Solubility decreases with the increase of temperature. Marble contains a small amount of calcium hydroxide. In the laboratory, calcium carbonate reacts with hydrochloric acid to produce carbon dioxide.