![]() ![]() The presence of ammonia ions prevents carrying out a qualitative detection of sodium, as the white amorphic sediment of meta-antimonic acid HSbO₃. The white crystalline sediment Na forms, which is soluble in alkalis. The reaction is carried out in a neutral or weak alkaline medium, in the absence of cations of other groups and ammonia ions.Ī reaction may also be carried out with potassium antimonate(V): The white crystalline sediment NaН₂SbО₄ forms (its formation can be accelerated by cooling the solution or rubbing a glass rod against the wall of the vessel). With the impact of potassium antimonate KH₂SbO₄ on dissolved table salt, the following reaction takes place: Impact of potassium antimonate on sodium ions The presence of cations of heavy metals may also interfere – for example, Fe³⁺, Bi³⁺, Hg²⁺ etc. The result may be distorted by the presence of ammonia cations NH₄⁺ or potassium cations (K⁺), only if their quantity exceeds the quantity of sodium ions by 20 times. This reaction can be considered specific for sodium ions (it makes it possible to establish the presence or absence of sodium cations in a solution more precisely (compared with a flame), as other cations of alkaline metals do not disguise the result). ![]() Click here for safe experiments with sodium compounds. A yellow crystalline sediment forms which is insoluble in acetic acid. The reaction is microcrystalline – to detect the effect, it should be carried out on a microscope slide (if the mixture is heated on the glass at the moment the reaction takes place, the sensitivity of the reaction increases). Sodium salts reacts as follows with uranyl zinc acetate (or zinc dioxourane(VI) acetate) Zn(UO₂)₃(CH₃СOО)₈ in the presence of acetic acid: ![]() Reaction with uranyl zinc acetate Zn(UO₂)₃(CH₃СOО)₈ It is important that the salt is purified from mixtures as much as possible – cations of other metals (for example potassium or lithium) may “disguise” the color of the flame. If a metal (for example platinum) wire is soaked in a sodium salt solution and put into the flame of a burner, the color of the flame should change to yellow. A reaction can also be carried out with a salt solution. If several salt crystals containing sodium cations are plunged into the flame of a burner, the flame turns green. ![]()
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