So we've learned in the past that are acid dissociation constant. Otherwise known as K. A. Is a way of gauging the strength of an acid. We know that if R. K. Value is greater than one then we're dealing with a strong acid. And if our K. is less than one then we're dealing with a weak acid. Now in addition to this we can say that the acid constant K. A. Tells us numerical value that an acidic hydrogen can be removed. So basically if we can convert our K. Two P. K. We can compare it to the ph of our solution to determine which one is the principal species within our solution. Is it the acidic form or the basic form that predominates. Now here if we're looking at a model product acid, if we have the ph being less than R. P. K. A. Then we're gonna say that the acid form is greater than the basic form. And then if we look at it the other way, if our ph is greater than R. P. K. A. Then our asset form is less than our basic form. The way you can think of it is we have these two forms H. A. And a minus. And in between them is this line here at this line we can say that this is our P. K. A. If your ph happens to be less than this P. K. A. Then we'll exist in our acidic form here. But if all of a sudden we crank up the ph where it surpasses P. K. A. Then we'll be on this side of the fence. So exist in our basic form. Now what would your um what would be the principal species if your ph equaled your P. K. Well if your ph equaled your P. K. You'd be exactly on this dividing line here and on this dividing line, both forms exist together. So if your ph equal equal your P. K. A. That would mean that you have 50% of this acid form and 50% of the basic form. And that is true in P. H. Equals P. K. A. Now this relationship of PH and PK can also be expanded outwards to die product as well as polyp product acids. So we'll take a look at those situations as we investigate each of the example problems left below. So click on the next video and see how we approach. Example one.