So in our last lesson video, we showed an example of the Thai trey shin of a strong acid with a strong base just to refresh your guys. Memories on how tight rations work now because most acids and biological systems are weak acids. In this video, we're going to focus our attention on the Thai tray shin of weak acids. Now, in our last lesson video, we also said that titrate Asians can reveal the PK a values for weak acids. And so the point on a tight tray shin curve that reveals the PKK value of a weak acid is called the inflection point, also known as the midpoint, because that's exactly when half of the acid has been neutralized. And so the point where half of the acid is neutralized is the exact point where the pH of the solution is equal to the P K. A value for ah, weak acid. And so recall from our previous lesson videos that when the pH of the solution is equal to the PK of an acid, that is the exact point where the concentration of conjugate base is equal to the concentration of conjugate acid and so looking down below at our titrate in curve Noticed that this is the tie, Trish in of a weak acid with a strong base, meaning that the weak acid here is going to be our Anna light solution. And of course, the strong base over here is going to be the Thai trahant. And so notice that the equivalence point that we mentioned earlier is being indicated by this blue line and point. And so notice that the equivalence point is showing up at exactly 0.5 or half of the Moller equivalents of titrate that of being added. And so this point, where half of the Mueller equivalence of Titan of being added corresponds with a pH value, and this pH value is going to be the pH that equals the PKK value for a weak acid. And so over here in this chart, you can see that the inflection point, which is also known as the midpoint, is going to be the exact point where the pH of the solution is equal to the P K. A value for the weak acid. And this applies for a week assets on Lee. And so we already know from our previous less video that equivalence points are also known as endpoints because that is essentially the end of oven acid because 100% of the acid has been neutralized. And this is the exact point where the concentration of Anna Light is going thio equal the concentration of Titra or the amount of titrate that has been added. And so over here in our titrate in curve, you can see the equivalence point is being indicated by the green dotted line and point here. And so you can see that it's the exact point where the concentration of Anna Light, which we said was the weak acid, is equal to exactly equal to the concentration of Thai trahant, which we said is a strong base and sodium hydroxide is a strong base, and so you can see that it's a it's showing up the equivalence point, showing up at exactly one Moeller equivalent of Thai trahant that's being added. But which, uh, in our previous lesson video, where we showed, uh, the tight creation of a strong acid with a strong base, we said that the pH shows up at a Ph of seven for the equivalence point. But that is not always the case. The equivalence point does not always equal a Ph of seven. It on Lee equals a Ph of seven when you're performing the Thai tray shin of a strong acid or base with a strong acid or base. And so what you'll see here is that, uh, the pH of the equivalence point depends on the concentration of hydrogen ions, when exactly one Moeller equivalent of Thai trinh is added, and so here for the Thai tradition of a weak acid with a strong base, you can see that when exactly one Moeller equivalent of Titan is added, notice that it corresponds with a pH that is not seven. Instead, it's about a Ph of 8.5. And so that's it's something important to keep in mind about the tight rations of weak assets that the equivalence point do not equal a Ph of seven. And so we'll be able to apply some of the concepts that we've learned here moving forward and our practice problems. So I'll see you guys there
