00:01
This question here asks us to consider the way the following ions act in solution.
00:06
So we're asked to consider p .o4 -3 minus the phosphate ion, h -p -o -4 -2 minus, and h2 -p -o -4 minus.
00:18
And so looking at this, it's pretty obvious that these are the various stages of dissociation of h3 -p -o -4, which is a triprotic acid.
00:28
And we're told that each of these can act as a base.
00:34
And so in other words, it's just going to go from its current form to being a form with one more hydrant.
00:40
So the p .o4 .3 minus goes to h .p .o .42 minus and so on, like that.
00:48
And so we're asked to find the kb of each of them acting as a base.
00:51
And so that means that it's going to, using the relationship that k .a.
00:56
Times kb of the conjugate base of an acid equals 10th to negative 14th, we can figure this out.
01:03
So looking at this first on p .o .4 .3 minus, it is the conjugate base of h .p .o .4 -2 minus.
01:09
And so what we're looking for is we want to find the ka of hpo42 minus, plug it into here, and we can find kb.
01:17
And then we can do the same thing for h .p .o .4 -2 minus, but instead we'll look for the ka of its conjugate acid and so on and so forth.
01:25
And so if we do that, i'm going to erase this here over here...