What is sodium hydrogen sulphate?

Sodium hydrogen sulphate is an acid salt of sodium and sulfuric acid. This substance is designated by the formula NaHSO4. Sodium hydrosulfate is a transparent crystal that does not have a specific odor. The molar mass of this substance is 120.06 grams per mole, and its density is 2.472 grams per centimeter cubic. It melts at a temperature of +186 ° C. When the substance is heated, two polymorphic transitions can be observed-at a temperature of +140 ° C and +170 ° C.

Sodium hydrosulfate can react with alkalis, passing into the sulfate reaction. Thus, when it interacts with sodium hydroxide, sodium sulfate and water are formed. With a strong heating of this substance (up to +250 ° C or more), it splits into sodium pyrosulfate and water.

In ordinary condition, sodium hydrogen sulfate does not react with other substances, however, when sintered at a temperature of more than +450 ° C, it is able to react with salts and oxides.

The practical significance of this substance is large: it is used in non-ferrous metallurgy (as flux), it also acts as a reagent when transferring oxides to sulfates. It is a strong denaturing agent. It is widely used in cooking (officially registered as food additive E514).

However, despite its importance in human life, sodium hydrogensulfate can be dangerous: being a strong alkali, this substance is very corrosive, it can leave severe burns if it gets on the skin, causing considerable harm and eye mucosa. The greatest danger is its entry into the gastrointestinal tract. Also, inhalation of vapors of the substance is extremely harmful.

Due to the negative impact of sodium hydrogen sulfate on the human body, this substance is marked with the international symbol "Dangerous", which is a square of orange colored, cut by two diagonal black strips. This sign speaks of the danger of the substance not only for man, but also for the environment, and also about the limitations imposed on its production.

To produce sodium hydrogen sulfate, it is necessary to conduct a reaction between concentrated sulfuric acid and caustic soda, with sulfuric acid being in excess. As a result of this reaction, sodium hydrogen sulphate and water are formed.

However, before taking on the preparation of this substance, you need to get the sodium itself. Getting sodium is not too complicated procedure, and some of the methods are possible even at home.

One of the very first ways of obtaining sodium is the reaction of reducing sodium carbonate (Na2CO3) with coal at high temperature (about +1000 ° C). Its result was the production of pure sodium and the release of carbon monoxide. Carrying out this reaction was not too time consuming, but because of the separation of carbon monoxide it became very dangerous.

Therefore, another method was invented, namely, electrolysis of molten sodium chloride. The advantage of this method is not only its relative safety, but also a lower heating temperature of the substance than at the reduction: +600 ° C instead of +1000 ° C. This method can be used at home - if, of course, there is the possibility of heating sodium chloride (common table salt) to the specified temperature.

Based on sodium - the most chemically active element of the periodic table - get a substance that is related to sodium hydrogen sulfate and no less important for mankind. This substance is sodium hydrosulfide, the acid salt of hydrogen sulfide and sodium. It is white crystals, designated by the formula NaHS. It is obtained by passing hydrogen sulphide through a solution of sodium sulfide, and also by passing hydrogen sulfide through a solution of sodium hydroxide.

Sodium hydrosulfide reacts with alkali and acids, it is easily oxidized by oxygen. Melt turns black. It is used widely enough: it is part of the means used to remove excess layers of skins, is common in the textile industry, is used as raw material for the production of many colorants, butiphos.