Class 12 Chemistry P Block Elements Properties of oxy acids of halogens

Properties of oxy acids of halogens

 Acidic strength :

  • The acidic strength of these oxy acids having same oxidation number decreases with increase in size because the electro negativity decreases as we go down the group from chlorine to iodine.
  • This is the reason that to withdraw electrons from oxygen atom towards itself decreases from chlorine to iodine.
  • As a result the tendency to pull the electrons from hydrogen decreases and the release of hydrogen ion becomes difficult.
  • The order of acidic strength is :

                 HClO<HClO2<HClO3<HClO4

  1. Oxidizing power and thermal stability :
  • As the oxidation number increase the oxidation power decreases in order :

                HClO>HClO2>HClO3>HClO4

  • This is because the halogen oxygen bond becomes more covalent. As a result the thermal stability increases. Thus the hypohalites are stronger oxidizing agents than perhalates.
  • With increase in oxidation number of halogen the thermal stability of both the acids and salts increases thus the stability of oxy acids are in order:

                 HClO<HClO2<HClO3<HClO4

  •  As the number of oxygen atoms increases in an ion, there is greater dispersal of negative charge therefore, greater is the stability of ion formed.
  • The acidity of oxo- acids of different halogens which have same oxidation number decreases from chlorine to iodine. This is due to decrease in electro negativity with increase in size.

 

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