--%>
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 : Describe physical adsorption and its

    When the forces of attraction existing between adsorbate and adsorbent are van der Waal's forces, the adsorption is called physical adsorption. This type of adsorption is also known as physisorption or van der Waal's adsorption. Since the forces existing between adsorbent and adsorbate are very w

    		•
  • Q : Describe various systems for

    Common system According to this system, the individual members are named according to alkyl groups att

    		•
  • Q : Quantum Mechanical Operators The

    The quantum mechanical methods, illustrated previously by the Schrödinger equation, are extended by the use of operators. Or, w

    		•
  • Q : Describe the function of the

    Briefly describe the function of the monosaccharide?

    		•
  • 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 : Excel assignment I want it before 8 am

    I want it before 8 am tomorow please. I am just wondering how much is going to be ?

    		•
  • Q : Explain the polymers and its types.

    Polymers are the chief products of modern chemical industry which form the backbone of present society. Daily life without the discovery and varied applications of polymers would not have been easier and colourful. The materials made of polymers find multifarious uses and applications in all walk

    		•
  • Q : Vitamines 7 enzyme cofactor what is the

    what is the relationship between vitamins and enzyme cofactors

    		•
  • Q : Problem on Clausius equation of state

    If a gas can be described by the Clausius equation of state: P (V-b) = RT Where b is a constant, then:  (a) Obtain an expression for the residual vo

    		•
  • Q : Depression in the freezing point When

    When 0.01 mole of sugar is dissolved in 100g of a solvent, the depression in freezing point is 0.40o. When 0.03 mole of glucose is dissolved in 50g of the same solvent, depression in the freezing point will be:(a) 0.60o  (b) 0.80o

    		•