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Homework Help: Oxo acids, attraction between Y element and oxygen

  1. Jun 12, 2016 #1
    I have read (I don't remember the source, and have it only in my notes now) that oxo acids can be strong if Y element has a high electronegativity.
    If generic formula for oxo acids is HnYOm, than if Y has high electronegativity, it will cause the acid to become strong because Y will be "happy to be on the right side of equation because there are more electorns on the molecule"
    HnYoM + H2O -> (double arrows here) H3 + Hn-1YOm
    "the more electronegative Y is the better it can stabilize the Y-O product and the stronger the acid will be.
    I don't get it. I will be grateful for your help and explanation.
    For example:
    HOI is weaker than HOCl
    O has electronegativity of 3.5, I 2.5, Cl 3.00
    I don't see how the above explanation works.
    What I can assume from the numbers is that O and Cl has a small difference in their electronegativity of 0.5, which might mean that electrons are more or less equally shared between these elements; while the difference between O and I is 1, hence electrons are more likely to be around O. Would it mean that the O-Cl bond is stronger than O-I one and hence it weakens the H-O bond, allowing H to go?

    Please, help me.
    Thank you very much!
  2. jcsd
  3. Jun 17, 2016 #2
    Thanks for the post! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?
  4. Jun 19, 2016 #3
    Sad that I have not received any responses. Please, let me know if I have badly stated the question.
  5. Jul 24, 2016 #4
    Here is how I understood it when I learnt it. Hope it helps you too.

    When we compare oxoacids across a group the strongest oxacid is the one which has the highest EN. This is because if the element has high EN it can pull the shared electrons of O-Y bond with greater ease. Now oxygen, by virtue, prefers the presence of electrons around it. Here in this case it can draw the electrons from the O-H bond closer towards itself. Thus the hydrogen gains a partial positive charge, making it easier for its extraction as H+.

    You were almost correct. It is not the bond strength but the EN difference which allowed the H+ to leave.
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