Alkalis are the strongest bases very well soluble in water. The chemical formula of such substances looks as ROH where R is alkaline or alkaline-earth metal. The correct chemical name of alkalis — hydroxides.
In usual conditions of alkali represent flavourless colourless solid substances. All alkalis are the bases, but not all bases can be considered alkalis.
Properties of alkali
One of the most important properties of alkalis is the hygroscopicity. That is such substances not only are well dissolved in water with rough allocation of heat, but also are capable to absorb moisture from air. Water solutions of alkalis soapy to the touch and also have no smell. Only compounds of alkali with some third-party volatiles can smell.
Are capable to absorb and connect such hydroxides not only molecules of water, but also, for example, sulphurous gas, hydrogen sulfide, nitrogen dioxide. Besides water, alkalis can be dissolved in alcohols methyl and ethyl. They are capable to maintain temperatures to 1000 °C.
One more important feature of hydroxides of this type is the ability to react with acids with formation of salts and waters (neutralization reactions). Also alkalis well react with solutions of salts, transitional metals, acid oxides.
Such hydroxides belong to the class of dangerous substances. In the concentrated look they are capable to corrode organic chemistry, including skin and mucous the person. Fusions of alkalis can easily destroy even phosphorus and platinum.
Popular alkalis
The type of alkali which is the most demanded in the world is caustic rubbed or sodium hydroxide. In life this substance is called caustic soda. Caustic rubbed very widely it is used in the food industry and also by production cosmetic, disinfecting and detergents.
Hydroxide of calcium or extinguished lime can be considered as the second most popular kind of alkali. Hydroxide of calcium is widely used in construction as finishing material. Also this very good disinfectant. Use this alkali and in agriculture for neutralization and improvement of sour soils.
As alkalis are dangerous substances, during the work with them and the means made on their basis it is necessary to be careful. To get poisoned with couples when using alkali as use, for example, of acid, it is impossible. But chemical burns at direct contact such hard-to-remove hydroxides are capable to cause even stronger, than acids.