The accompanying graph shows the titration curves for two monoprotic acids. (d) Estimate the pKa of the weak acid.

Video transcript

Hey everyone, we're given the dehydration curves for two mono product assets and were asked, what is the P K A. For the weak acid first? Let's go ahead and determine which curve is the weak acid. Now, when we look at curve a we can see that we have a lower initial ph and a steeper equivalence point region, which will be this region right here, in comparison to our curve B, which has a less steep equivalence point region and a higher initial ph. And because of these reasons, this means that curve B will be our weak acid. Now infiltrations of a weak acid at the volume halfway to our equivalence point, our ph will equal R p K A. So again, that's at halfway of our equivalence point. So looking at curve B, we can see that our equivalence point is going to be at 40 mL. Now using the knowledge, we just stated, We know that at half of our equivalence point RPH will equal RPKA. So this means at 20 ml RPH will equal RPK. So looking at 20 ml We can see that we're at about a ph of 6.5, Which will also be the value of RPKA. So 6.5 will be our final answer. Now, I hope that made sense. And let us know if you have any questions