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Ch.18 - Aqueous Ionic Equilibrium

Chapter 18, Problem 61b

The graphs labeled (a) and (b) show the titration curves for two equal-volume samples of monoprotic acids, one weak and one strong. Both titrations were carried out with the same concentration of strong base.

(ii) Which graph corresponds to the titration of the strong acid and which one to the titration of the weak acid?

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Hi everyone for this problem. It reads the images below show the titillation curves of equal amounts of weak and strong mono protic acid tight traded with the same concentration of strong base. We have two images here. And the question for this is which of the following statements is true. Okay, so let's take a look at answer choice. A graph A corresponds to the tight rations of a strong acid and graph B to the weak acid. So we need to understand what our titillation curves show us for strong and weak acids. Okay, so for strong acids, the titillation curve is going to have a lower ph initially. Okay, so that's one thing we need to pay attention to here. Which one has a low ph initially it looks like A. Does the second thing strong acid titillation curve has is it has a flatter initial region. Okay. And lastly it has a sharp rise at the equivalence point. Okay, so based off of that when we compare the two, it seems as though or it is a is going to be the strong stronger acid. Okay, now, for a B we said strong with the characteristics of strong acid for a weak acid titrate in curve or one of the other things that we can look at is the equivalence point. Okay, so for the equivalence point of strong acids, the ph is going to be neutral. Okay, so neutral is a ph of seven. So, at the equivalence point, the ph will be neutral, which is another reason why A is a strong acid for a weak acid, the equivalence point is going to be basic. Okay. And so if we look for the equivalence point of B, we can see that the ph reflects the ph of a basic a basic ph Okay, so that means this is going to be a weak acid. So let's go back and look at our answer choices. Graph A corresponds to that tree iteration of a strong acid and graph B to the weak acid. This is going to be correct. So let's go ahead and highlight A as correct. But let's still go through the other answer choices be Graph A corresponds to the tri trey shin of a weak acid and graph B to the strong acid. This is not true because it's the opposite of A. And we said A is correct. Okay. See both graph A and B shows the tip tray shin of weak acids. This is not true. One is strong, one is weak and D both graph A and B shows the titillation of strong acids. This is not correct. And E. None of the above. Okay, so answer choice A is our only correct answer choice here. So, graph A is the strong acid and graph B is the weak acid. That's the end of this problem. I hope this was helpful