Question

I've searched everywhere for this answer, but I've had no luck. I'm currently helping a friend with ampholytes and polyprotic acids, but I'm not sure if H30+ and OH- would be ampholytes, polyprotic acids or neither. Any help would be much appreciated. Thanks.

Answer 1

1) HCO3^-, Al(OH)3, and any zwiterion, are ampholytes since they can react with an acid or a base under the proper conditions.

2) H3PO4, H2PO4^-, H2SO4, etc are polyprotic acids since they have more than one acid hydrogen (can donate more than one proton)

Answer 2

thanks GK

Answer 3

This is a really challenging question. I believe GK clearly defined what ampholytes and polyprotic acids, but from the original question what would H30+ then be without combining it and OH- be? ampholytes or polyprotic acids? these have not been answered from above

Answer 4

Additional comments:

1) Using the Bronsted-Lowry model of acids and bases, H3O+ is an acid since it can donate a proton:
H3O+(aq) + NH3(aq) --> NH4+(aq) + H2O
H3O+ is not an ampholyte since it is not known to accept a proton from another proton donor (acid). It does not have a conjugate acid (H4O+ does not exist).

2) Under unusual conditions, OH- could act as an ampholyte. Its conjugate bas is O^-2
a) Basic behavior:
OH-(aq) + H3O+(aq) ----> H2O + H2O --> 2H2O

b) Acid behavior:
OH- + OH- --> H2O + O^-2
One of the OH-'s donates a proton to the other forming H2O and O^2- . This cannot happen in a water solution but it does happen n the solid state:
Ca(OH)2(s) + heat ---> CaO(s) + H2O(g)