Two 25.0-mL samples, one 0.100 M HCl and the other 0.100 M HF, are titrated with 0.200 M KOH.

d. Sketch each titration curve.

Video transcript

All right. Hello everyone. So this question says that 0.200 molar potassium hydroxide is used to titrate 50.0 mL samples of 0.200 molar H three and 0.200 molar H two individually match them to their corresponding titration curve. And right underneath the text of the question are two titration curves labeled A and B. We also have two different entry choices labeled A and B proposing which of the two curves corresponds to which titration in particular. Now recall first and foremost that potassium hydroxide is an example of a strong base because it's a base with hydroxide and a group one metal. Now hno three thats nitric acid is an example of one of the seven strong assets H two. On the other hand, or nitrous acid is not among the seven strong acids, which means that it is in fact a weak acid. And so by understanding the differences in their strength as acids, we can compare their respective titrations with a strong base like potassium hydroxide. So here we're going to have two different titration curves essentially one between a strong acid and a strong base and another one between a weak acid and a strong base. So here I'm going to go ahead and scroll down so I can open up some space for these comparisons here. All right. So first off with the strong acid, strong base titration curve recall that we're generally going to see a lower initial ph due to the fact that we have a stronger acid in solution. So we have a low initial Ph and the equivalence point of the titration curve is going to be at ph seven because there's going to be a neutralization between the strong acid and the strong base. Now, in addition to this before and after the equivalent point, we should expect to see a flattening of the curve with a sharp rise at the equivalence point in between them. So here we can compare these factors to the titration between a weak acid and a strong base. Starting off a weak acid, strong base titration curve can be expected to have a relatively higher initial ph. It's still going to be acidic. The Ph itself is going to be relatively acidic but less so than the strong acid strong base curve. So here at the equivalence point, the PH can also be expected to be slightly greater than seven because the base, it in this case would be stronger than the acid being used. And in addition to this before the equivalence point or rather before and after the curve is not expected to be as flat as the strong acid strong base titration. So with these comparisons in mind, let's go ahead and scroll up again. So we can consider both curves starting off with that initial Ph. We can see that the initial ph of curve A is slightly lower than that of curve B and both of these regions or sorry, both of these curves have a steeper region more or less in the middle of the curve which is going to contain the equivalence point. Now, before and after the steeper region curve A does appear to be a little bit flatter, then curve beat us. So to go ahead and confirm these observations, let's go ahead and also compare their equivalence point which is going to be the midpoint of the steeper region in these two curves in curve A that equivalence point or that midway point of the steeper region is going to be at about seven. Whereas for curve B that equivalent point is approximately ph eight. So here we can see that curve A is going to correspond to that strong acid strong base titration for the following reasons that we described previously. So here titration curve A is going to represent the titration between HNO three and koh that's potassium hydroxide. Whereas curve B represents the titration of HNO two and potassium hydroxide. And so our answer is going to be option A in the multiple choice which reads as follows titration curve A corresponds to the titration of HNO three with koh. While titration curve B corresponds to the titration of HNO two with koh. And so with that being said, thank you so very much for watching. And I hope you found this helpful.