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Posted: Sat Dec 08, 2018 5:51 pm
For oxyacids, what is it about molecules with more oxygen atoms that make the molecules more acidic?
Posted: Sat Dec 08, 2018 6:00 pm
If the central atom is not the same in a set of oxoacids then the molecule with the central atom with the highest electronegativity will be the most acidic.
If the central atoms are the same for a group of oxoacids then we must see the number of Oxygens that are attached to the central atom. The more oxygens on the oxoacid the more acidic it is.
I just came out of a chem review session and I was told that on the exam we will have to order from most to least acidic, but they will never make it so that we must confirm an oxoacid with a non oxoacid. It is always comparing oxoacids with oxoacids and non with non. (This part was just a little extra, but maybe it'd help).
Posted: Sat Dec 08, 2018 6:15 pm
This is because the greater the oxidation number of the central atom, the stronger the acid. When the oxidation number of the central atom is high, it has a greater electron withdrawing power (pulling electrons towards it), hence weakening the O-H bond (making it easier to lose the H/proton).
Posted: Sat Dec 08, 2018 11:59 pm
Well attaching more oxygen molecules helps distribute the negative charge of the conjugate base over more atoms and so that makes the proton less strongly attracted to the oxygen atoms in the conjugate base and thus you have a stronger acid.
Posted: Sun Dec 09, 2018 11:27 pm
If the acid has the same base element the strength of the oxyacid depends on the number of oxygens. If the oxyacid has a different base element the stronger oxyacid is the one with a more electronegative base.