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    Selenistaya acid 2804900000

    Selenistaya acid
    Selenistaya acid
    Selenistaya acid
    Selenistaya acid
    Selenistaya acid
    Selenistaya acid
    Selenistaya acid
    Selenistaya acid
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    • Availability: In stock
    • Packaging: кг.
    • SKU: 300448168
    • ТН ВЭД: 2804900000
    • The country of manufacture: Евро Союз
    • Status: предоплата
    • Brand name: Европа
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    The content of selenium in the earth's crust is 1 · 10 –50 %, tellurium - 1 · 10 –7 %, and polonium - only 2 · 10 –15 %. The latter is one of the least common elements in nature. It is radioactive and has hardly been studied chemically.

    For selenium and tellurium the most characteristic is the joint presence with such metals such as Pb, Cu, Hg, Ag and Au. However, independently minerals Se and Te are extremely rare, usually only in the form of impurities to similar minerals sulfur .

    The main sources of obtaining selenium and tellurium sulfuric acid production wastes ( sulfur dioxide . Recovery is initially conducted at 10-12 n hydrochloric acid , and only selenium is released. Then, after strong dilution liquids water , stands out tellurium .

    When selected from selenium are poisonous.

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    2) For selenium and tellurium several allotropic modifications are known, which, however, are still relatively little studied. Selenium is consumed mainly in the manufacture of AC rectifiers, and Tellur in the production of lead cables . Additive it (up to 0.1%) to lead greatly increases hardness and elasticity the latter Such lead is also more resistant to various chemical influences.

    From the chemical side selenium and tellurium are generally very similar to sulfur . From metalloids they most vigorously interact with fluorine and chlorine , and with oxygen (as well as sulfur ) are connected only after preliminary heating. With gaseous hydrogen partially reacts at elevated acids act on them, selenium-hydrogen (H < sub> 2 Se) and hydrogen telluride (H 2 Te). Both of them are colorless gases with characteristic unpleasant odors. Solubility them in water is about the same as that of hydrogen sulfide , and solutions show a clearly expressed acidic reaction . Some of the most important properties of the compounds under consideration are compared in the table below and in Fig. 108 with similar properties H 2 O and H 2 S. For an approximate orientation in the size of the corresponding molecules the radii ions E 2– are also given.

    From the data in the table you can see that H 2 Se and H 2 Those are acids stronger than acetic acid (К = 2 · 10 –5 ​​). Both compounds (especially H 2 Te) are very unstable and easily decompose. Oxygen air they are gradually oxidized in the gaseous state and especially in solution already with the usual temperatures . In general, the reducing properties are characteristic of H 2 Se and H 2 Those even more than for acid (K 1 = 2 · 10 –3 , K 2 = 5 · 10 –9 ) can be obtained by reactions : 3Se + 4HNO 3 + H 2 O = 3H 2 SeO 3 + 4NO. Its oxidizing properties are not particularly pronounced. So, it oxidizes J ', but is not able to oxidize Br. From salts Н 2 SeО 3 it should be noted slightly soluble selenite

    / a> (K 1 = 2 · 10 –3 , K 2 = 5 · 10 –9 ) can be obtained by reactions : 3Se + 4HNO 3 + H 2 O = 3H 2 SeO 3 + 4NO. Its oxidizing properties are not particularly pronounced. So, it oxidizes J ', but is not able to oxidize Br. From salts Н 2 SeО 3 it should be noted slightly soluble selenite

    / a> (K 1 = 2 · 10 –3 , K 2 = 5 · 10 –9 ) can be obtained by reactions : 3Se + 4HNO 3 + H 2 O = 3H 2 SeO 3 + 4NO. Its oxidizing properties are not particularly pronounced. So, it oxidizes J ', but is not able to oxidize Br. From salts Н 2 SeО 3 it should be noted slightly soluble selenite

    ) can be obtained by reactions : 3Se + 4HNO 3 + H 2 O = 3H 2 SeO 3 + 4NO. Its oxidizing properties are not particularly pronounced. So, it oxidizes J ', but is not able to oxidize Br. From salts Н 2 SeО 3 it should be noted slightly soluble selenite

    ) can be obtained by reactions : 3Se + 4HNO 3 + H 2 O = 3H 2 SeO 3 + 4NO. Its oxidizing properties are not particularly pronounced. So, it oxidizes J ', but is not able to oxidize Br. From salts Н 2 SeО 3 it should be noted slightly soluble selenite

    Its oxidizing properties are not particularly pronounced. So, it oxidizes J ', but is not able to oxidize Br. From salts Н 2 SeО 3 it should be noted slightly soluble selenite

    Its oxidizing properties are not particularly pronounced. So, it oxidizes J ', but is not able to oxidize Br. From salts Н 2 SeО 3 it should be noted slightly soluble selenite

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