Very often this substance is called Bertholite salt, after the chemist from France - Bertollet, who discovered potassium chlorate, the formula of which is written as KClO3. In his experiments, Bertollet received the substance by exposure to an alkaline solution of chlorine at a high temperature during the reaction. As a result of this reaction, potassium chloride, potassium chlorate, and three water molecules were obtained. If you analyze the formula of a substance, you should pay attention to the fact that Bertoletova salt is very rich in oxygen.
Externally, Bertolet's salt is a colorless crystal that has a density of 2.32 grams per centimeter cubic, at a temperature of 356 ° C they begin to melt, and at 400 ° C they decompose. Solubility is 3.25 grams per 100 grams of an aqueous solution at 0 ° C. With increasing temperature, the solubility of bertholite salt also increases.
At a sufficient heating temperature, it very easily “partes” with oxygen atoms, which can be represented by the following equation: 2KClO3 = 2KCl + 3O2.
As a rule, a reaction is carried out in order to obtain bertholite salt, during which chlorine gas is passed under forced air pressure through high-temperature solutions of potassium hydroxide or carbonate.
During the reaction with hydroxides, the chlorine stream is directed through a 30% potassium hydroxide solution, and when carbonates are used as a filter, this is a potash solution concentrated to the level of 45%.
It is important that, during such an operation, the crystals of the substance formed do not clog the gas vents, therefore, it is necessary to consider the use of an alonge during the reaction.
Then, potassium chlorate obtained in the form of crystals should be filtered through glass wool and dried well. In this technology, the use of filters made of paper materials should be avoided, because Berthollet salt can react with the fiber contained in the paper and cause an explosion.
There are quite a few ways with which you can get Berthollet salt. We will describe some of them.
Mark 5-10 grams of permanganate into a Würz flask, then add about 30-70 millimeters of concentrated hydrochloric acid using a funnel, which must first be inserted into the flask with the solution. It is better to do this drip, because in this way the rate of chlorine formation during the reaction is more effectively regulated.
Potassium chlorate can also be obtained by the electrolytic method. To do this, it is necessary to decompose a concentrated solution of ordinary table salt by the action of an electric current. Such a reaction is carried out as follows. A certain amount of sodium chloride is taken, best of all non-iodized and coarse-grained. Two graphite electrodes, a glass, electric wires, a chemical glass, and a bottomless Wurz flask are used as equipment. The wires are connected to a step-down transformer through a rectifier that converts alternating current into direct current . Electrolysis is carried out at a solution temperature of 70 - 80 degrees.
As a result of the reaction, potassium chloride is formed, which dissolves much better in water than the Bertholetic salt. Therefore, after the end of the reaction, potassium chlorate settles on the walls of the vessel, and potassium chloride remains dissolved in water.
When performing various kinds of experiments and reactions with a substance, it is necessary to pay attention to the fact that its mixtures, especially with organic substances, are extremely explosive, and also “sensitively” react to any kind of shock, exposure to high temperatures. Some of the most active substances that react with barletol salt include sulfur, antimony, carbon black, red phosphorus, starch, and even sugar.
Of particular danger is potassium perchlorate - potassium perchlorate. This compound has a very strong explosiveness, therefore it is used as a “working substance” in military grenades, shells and mines. For long periods of storage, this compound can self-ignite.