We encounter many chemical compounds very often, and without even noticing it. One of them is potassium nitrate, or Indian nitrate. The crystalline powder has firmly entered our life: we eat it (as additives in various products), we use it in agriculture as a very valuable and useful fertilizer, well, we just rejoice, looking at some products in which it is present (fireworks).

Potassium Nitrate: Formula and Description

Potassium nitrate: formula, preparation, application

It is an inorganic compound having the formula KNO3. - salt formed by nitric acid and sodium. His crystals are colorless and odorless. The substance is not volatile, but has poorly pronounced hygroscopic properties (that is, the ability to absorb moisture, even from air, but in small quantities). Potassium nitrate is practically non-toxic and harmless to humans and animals. The crystals have an elongated needle shape. Very soluble in water (using electrolysis of potassium emitted from it), as well as in hydrazine, glycerin, liquid ammonia. A recrystallization method is sometimes used to purify potassium nitrate.

Natural deposits

Potassium Nitrate (KNO3 ) in the natural environment occurs mainly in the form of the mineral nitrocalite. Its largest deposit is in India. Hence the second name of the compound - Indian saltpeter. The mineral is formed as a result of a long process of decomposition of nitrogen-containing substances, the ammonia released during this process is bound by specific nitrobacteria. This reaction occurs at high air temperatures, which causes the prevalence of this mineral in countries with hot climates and high humidity.

Chemical properties

Potassium nitrate (formula KNO3   ) is a fairly strong oxidizing agent. In the ground state, it is very active, and sometimes it reacts with an explosion with combustible materials and some reducing agents. In reactions involving some organic compounds, he is able to ignite them. Nitrate is very unstable and when exposed to temperature decompose with the formation of nitrite and oxygen. Potassium nitrate is not an exception (equation: 2KNO3   → 2KNO2   + O2   ↑). This property of the compound indicates its very high fire hazard, which requires adherence to special storage rules.

The oldest way to get

Potassium nitrate is the salt that we started to receive in the Middle Ages. For this, large compost or dung heaps were used, niterites were called. They were made using limestone, various debris, layers of brushwood and straw to provide oxygen. From above, in order to keep all the emitted gases inside, they were condensed with sod. When organics began to actively decompose and rot, ammonia was released, which did not go out, but remained in layers of firewood and straw, gradually undergoing the process of nitrification and transformation, first into nitrogenous and then nitric acid. She, in turn, entered into chemical interaction with the limestone in the compost heap and resulted in calcium nitrate. Further, it was leached with ordinary ash (potash). In this case, calcium carbonate precipitated, and a solution of potassium nitrate was obtained. It was used primarily for the preparation of gunpowder. This is reflected by the following reaction:

Modern receipt

There are several ways to produce this substance. Here are the most used and common ones:

  1. Nitric acid is neutralized with potassium hydroxide.
  2. Absorption of nitrous gases by potassium hydroxide.
  3. Conversion method based on the decomposition of sodium nitrate with potassium chloride.

Application in agriculture

Indian nitrate is actively used in many areas of human activity. The main direction is agriculture, where potassium nitrate is used as a valuable fertilizer. It contains two components that are extremely necessary for plants for their active development. If they are introduced separately, then they mutually interfere with each other in normal learning, and if together - the process proceeds without any complications. This fertilizer is very quickly dissolved in the soil solution, which is also a big plus, the exposure time is minimized. The introduction of potassium nitrate under fruit trees in summer and autumn increases their cold and frost resistance.

Other areas of use

The second sphere, where potassium nitrate is actively used, is the production of black powder, which is currently mostly used for the manufacture of pyrotechnic products (military, specialized or entertaining).

The saltpeter in question is also used in the manufacture of solid rocket fuel, which is also called caramel because of its use in the production of sugar (sorbitol). It consists of 65% potassium nitrate.

The strong oxidizing properties of Indian nitrate have found application in metallurgy, namely, in the process of processing nickel-containing ores. Also, this substance is actively used in the field of glass industry, mainly for clarifying crystal, increasing the strength of products. Indian saltpeter is also used in the manufacture of enamels and other paints and varnishes.

One of the least effective and beneficial for humans areas where potassium nitrate is used is the food industry. There he is known under the code name E252 (preservative). It is used to increase the shelf life of products, since potassium nitrate slows down the process of reproduction of bacteria and various fungi. This substance is actively added to cheeses (hard, semi-hard, soft), sausages and meat products, canned fish, pastes made from goose liver. In addition, this additive improves the color of the product. Suffice it to recall the beautiful, but absolutely unnatural pink color of the sausage.

It is important to extract the following information: Supplement E252 is a carcinogen, that is, a substance that promotes cancer. Despite this, it is allowed for use on the territory of the Russian Federation and the countries of the Eurozone. This is the case when chemistry goes against a person.