--%>
Assignment Help - homework help

What are halogen oxoacids?

Fluorine yields only one oxyacid, hypofluorous acid (HOF). Chlorine, bromine and iodine form four series of acids with formulae: HOX, HXO2, HXO3 and HXO4, although many of these are known only in solutions or as salts.
    
The Hypohalous acids HOCl, HOBr and HOI are weak acids and are only formed in aqueous solutions by disproportionation of the halogen of the halogen water

X2 + H2O  1402_Phosphorus trichloride.png  HOX + HX (X = Cl, Br, I)

Salts of these acids are known as hypohalites, e.g. bleaching powder, CaOCl2 is a common example of this category.
    
The halic acids HClO3 and HBrO3 are also known as solutions, but iodic acid HIO3 exists as a white solid. Thus, the stability of acids increases with increase in atomic number of the halogen. These acids act as strong oxidizing agents, e.g. these oxidize halides to give halogens in acid medium.

OX3- + 5X- + 6H+  1402_Phosphorus trichloride.png  3X2 + 3H2O

The salts of these are called halates. Amongst the halates, sodium chlorate (NaClO3) and potassium chlorate (KClO3) are prepared on industrial scale. It is also known as 'Berthelot salt'. NaClO3 is a powerful weed killer, whilst KClO3 is used in fireworks and matches.
    
Perhalic acid i.e. perchloric, periodic acids as well as their salts perchlorates and periodates are known to exist. The perhalates (MXO4)are prepared by the electrolytic oxidation of the corresponding halates, MXO3.

4ClO3-  1402_Phosphorus trichloride.png  Cl- + 3ClO4-

The disproportionation of BrO3- to BrO4- is unfavorable, therefore per bromates are obtained only by oxidation of BrO3- by F2 in basic solution.

BrO3- + F2 + 2OH-  1402_Phosphorus trichloride.png  BrO4- + 2F- + H2O

Acidic character of oxyacids: the variation in the acidic character of the halogen acids in different oxidation states are summarized below:
    
The acid strength of oxyacid of the same halogen increases with the increase in oxidation number of the halogen. For example, among the different oxyacids of chlorine the acidic character follows the order

HOCl < HClO2 < HClO3 < HClO4

Reason: the acid strength can be explained on the basis Lowry-Bronsted concept that conjucate base of weak and is strong and conjugate base of strong acid is weaker.

   Related Questions in Chemistry

  • Q : Gibberella fusarium in bioremediation

    in bioremediation gibberella fusarium is used to break down____?

    		•
  • Q : Atmospheric pressure Give me answer of

    Give me answer of this question. The atmospheric pressure is sum of the: (a) Pressure of the biomolecules (b) Vapour pressure of atmospheric constituents (c) Vapour pressure of chemicals and vapour pressure of volatile (d) Pressure created on to atmospheric molecules

    		•
  • Q : What do you mean by the term hydra What

    What do you mean by the term hydra? Briefly define it.

    		•
  • Q : How haloalkanes are prepared from

    Alkyl halides can be prepared from alkanes through substitution and from alkenes through addition of halogen acids or through allylic substitution.    From alkanesWhen alkanes are treated with halogens, chlo

    		•
  • Q : Explain the molecular mass with respect

    During the formation of polymers, different macromolecules have different degree of polymerisation i.e. they have varied chain lengths. Thus, the molecular masses of the individual macromolecules in a particular sample of the polymer are different. Hence, an average value of the molecular mass is

    		•
  • Q : Concentration factor affected by

    Can someone please help me in getting through this problem. Which of the given concentration factor is affected by the change in temperature: (1) Molarity (2) Molality (3) Mole fraction (4) Weight fraction

    		•
  • Q : Colligative properties give atleast two

    give atleast two application of following colligative properties

    		•
  • Q : Relative lowering of vapour pressure

    explain the process of relative lowering of vapour pressure

    		•
  • Q : Surface Tension Vapour Pressure The

    The vapor pressure of small liquid drops depends on the drop size. Although the surface properties of a liquid are different from those of the bulk liquid, the special surface properties can be ignored except in a few situations. One is the case in which a liquid is dispersed into fine dr

    		•
  • Q : Explain the preparation of phenols. The

    The methods used for the preparation of phenols are given below:    From aryl sulphonic acids

    		•