Alkali is the basis or not? What are its properties?

What is acid or salt, most are well known. It is difficult to find a person who did not have a bottle of vinegar in his hands or did not use a food product in his life, without which practically any food seems fresh and tasteless. But what is an alkali? Is it the same as the foundation, or not? How is it different from acid? Such questions can puzzle anyone, so let's brush up on the knowledge that was once obtained in school.

Alkali is what?

To begin with, the compounds of metals with water in chemistry are called hydroxides. A substance of this type, formed by ammonium, alkali or alkaline earth metal, is called alkali. In turn, the base is an electrolyte, in which, in addition to hydroxide ions (OH ^- ), there are no other anions. Thus, it can be said that an alkali is any soluble base. Only such metals of subgroups Ia and IIa (those that go after calcium) can form such a hydroxide. Examples of such compounds are sodium alkali (formula NaOH), caustic barium (Ba (OH) ₂ ), potassium hydroxide (KOH), cesium hydroxide (CsOH), etc. They represent solid white substances, which are characterized by high hygroscopicity.

Properties of alkalis

Dissolution of such compounds in water is accompanied by considerable heat release. In group Ia, the strongest alkali is cesium hydroxide, and in group IIa it is the hydroxide of radium. An example of a weak compound of this type can serve as ammonia and hydrated lime. Corrosive alkali can dissolve in ethanol and methanol. In a solid state, all these substances absorb water and carbon dioxide from the air and slowly turn into carbonates. The most important property of alkali is that as a result of its reaction with acid, salt is formed - this feature is often used in industry. Through these connections, an electric current can pass, and therefore they are often used as electrolytes. Obtain alkalis by electrolysis of chlorides or through the interaction of alkali metal oxides with water. In industry, the first method is usually used, and the second method is used for the most part to produce slaked lime. In an alkaline medium, fat dissolves, and this property is widely used in the manufacture of soap. A number of bases can destroy plant and animal tissues, irritate the skin and destroy clothing. Alkalis can react with some metals (for example, aluminum) and are able to protect the steel from corrosion. They are resistant to heating - sodium hydroxide can be melted and brought to a boil, but it will not decompose. This alkali strongly differs from insoluble bases, some of which (for example, silver hydroxide) decompose already at room temperature. As well as acids, these substances require great care and high demands on compliance with safety recommendations. To protect the eyes when working with alkali, glasses are usually worn. They can be stored only in special vessels - drinking containers are absolutely not suitable for this.