echemi logo
Product
  • Product
  • Supplier
  • Inquiry
    Home > Chemicals Industry > Chemical Technology > Preparation and properties of halogen acid, halogen acid and their salts

    Preparation and properties of halogen acid, halogen acid and their salts

    • Last Update: 2021-06-18
    • Source: Internet
    • Author: User
    Search more information of high quality chemicals, good prices and reliable suppliers, visit www.echemi.com

    Halogenous acid and its salt

    Halogenous acid HXO 2 , halogen as the central atom adopts sp 3 hybridization, and the molecular configuration is V-shaped
    .

    1.
    Preparation

    HCIO 2 can be prepared by reacting halide with acid
    .

    Ba(ClO 2 ) 2 +H 2 SO 4 =2HCIO 2 +BaSO 4

    Use of the CIO 2 reaction with peroxide may also be prepared chlorite

    2C1O 2 +BaO 2 =Ba(ClO 2 ) 2 +O 2

    2.
    Nature

    Among the haloacids , only chlorous acid HCIO 2 can exist in the form of a dilute solution, but it is also extremely unstable and decomposes quickly to produce ClO 2 , which makes the solution yellow
    .

    8HCIO 2 =6ClO 2 +Cl 2 +4H 2 O

    Chlorite Although Shakespeare acid stable, but easy disproportionation reaction when exposed to heat or collision
    .

    3NaClO 2 = 2NaClO 3 +NaCl

    The aqueous solution of chlorite has strong oxidizing properties and is mainly used for bleaching fabrics
    .

    Halogen acids and their salts

    Halogen acid HXO 3 , halogen as the central atom adopts sp 3 hybridization, and the molecular configuration is triangular cone
    .

    1.
    Preparation

    Halogen element disproportionation in alkaline aqueous solution can produce halide salt
    .

    3X 2 + 6OH - = 5X - + the XO .
    3
    - + 3H 2 O

    The disadvantage of this method is that the utilization rate of the reactants is too low
    .

    Bromate and iodate can be prepared by oxidation of elemental substances with strong oxidants
    .

    Br 2 + 3Cl 2 + 6OH - = BrO .
    3
    - + 6Cl - + 3H 2 O

    I 2 +10HNO (concentrated) = 2HIO 3 + 10NO 2 +4H 2 O

    In the laboratory, the aqueous solution of halogen acid is prepared by the action of halogen acid salt and sulfuric acid.
    The concentration of sulfuric acid in the reaction should not be too high, otherwise the product HXO
    3 concentration is too high and explosive decomposition may occur
    .

    Ba(XO 3 ) 2 +H 2 SO 4 =2HXO 3 +BaSO 4

    2.
    Nature

    Halogen acids are strong acids, and the acidity is weaker in order of HCIO 3 , HBrO 3 , and HIO 3
    .

    The stability of halogen acid is higher than that of hypohalous acid, and HIO 3 has the highest stability and exists in solid form
    .
    However, HCIO
    3 and HBrO 3 only exist in the aqueous solution.
    When the concentration of the solution is too high, they will decompose explosively

    .

    8HC1O 3 =4HCIO 4 +2Cl 2 +3O 2 +2H 2 O

    4HBrO 3 =2Br 2 +5O 2 +2H 2 O

    The thermal stability of halogen acid salt is higher than that of the corresponding acid, but it also decomposes when heated
    .
    Common halide salts have KCIO
    3 , Nalo 3 and so on
    .

    4KCIO 3 =3KCIO 4 +KCI

    Under the action of the catalyst, KCIO 3 is heated and decomposed to generate KCl and O 2
    .

    2KCIO 3 =2KCl+3O 2

    The thermal stability of oxyacids and their salts can be explained by the theory of ion polarization
    .
    Due to the extremely strong polarizing ability of H+, oxygen-containing acids have lower thermal stability than their salts

    .
    The oxo acid or its salt of the same halogen has high oxidation number of halogen and high stability, because the high oxidation number of halogen has strong ability to resist cation polarization

    .
    The stronger the polarizing power of the cation, the more unstable the oxo acid salt

    .

    Both halogen acids and their salts have strong oxidizing properties
    .

    5HCIO 3 +6 P+9H 2 O=6H 3 PO 4 +5HCl

    HCIO 3 +S+H 2 O=H 2 SO 4 +HCI

    5HCIO 3 +3I 2 +3H 2 O=6HIO 3 +5HCI

    If HCIO 3 is excessive, Cl 2 will be formed in the product
    .

    KCIO 3 solid is mixed with concentrated hydrochloric acid, and the characteristic yellow CIO 2 is produced
    .

    8KCIO 3 +24HCI (concentrated)=9Cl 2 +8KCl+6ClO 2 +12H 2 O

    Among the three halogen acids, the most oxidizing is HBrO 3 , and the weakest is HIO 3
    .
    The oxidizability of halogen oxyacids is related to the stability.
    The oxidizability of oxyacids with poor stability is generally stronger, such as the order of oxidation:

    HCIO>HCIO 3 >HCIO 4

    Under alkaline conditions, KCIO can oxidize Kl, while KCIO 3 can oxidize KI under acidic conditions
    .

     

     

    This article is an English version of an article which is originally in the Chinese language on echemi.com and is provided for information purposes only. This website makes no representation or warranty of any kind, either expressed or implied, as to the accuracy, completeness ownership or reliability of the article or any translations thereof. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to service@echemi.com. A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately.

    Contact Us

    The source of this page with content of products and services is from Internet, which doesn't represent ECHEMI's opinion. If you have any queries, please write to service@echemi.com. It will be replied within 5 days.

    Moreover, if you find any instances of plagiarism from the page, please send email to service@echemi.com with relevant evidence.