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.
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)
thanks GK
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
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)
Ampholytes are substances that can act as both an acid and a base. Polyprotic acids are acids that can donate multiple protons (H+ ions). In the case of H3O+ (hydronium ion) and OH- (hydroxide ion), we can determine whether they are ampholytes, polyprotic acids, or neither by considering their acid-base properties.
1. H3O+ (hydronium ion):
H3O+ is formed when a water molecule (H2O) donates a proton (H+) to another water molecule. It acts as an acid by donating the proton and can also act as a base by accepting a proton. Therefore, H3O+ can be considered an ampholyte since it can exhibit both acid and base behavior. However, it is not a polyprotic acid as it can donate only one proton.
2. OH- (hydroxide ion):
OH- is formed when a water molecule accepts a proton. It acts as a base by accepting a proton and can also act as an acid by donating a proton. Therefore, OH- can also be considered an ampholyte since it can exhibit both acid and base behavior. However, it is not a polyprotic acid as it can donate only one proton.
In summary, both H3O+ and OH- can be considered ampholytes as they can act as both acids and bases. However, they are not polyprotic acids since they can donate only one proton.