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Current time:0:00Total duration:2:56

Video transcript

the initial pH and the equivalence point are plotted on the graph below accurately sketch the titration curve on the graph below mark the position of the half equivalence point on the curve with an X all right so we have they show they show us the initial pH right over here and they also show us the equivalence point right over here and instead of pH of we actually saw that in the last problem with the equivalence the equivalence point or actually a couple of problems ago the equivalence point was measured the pH at the equivalence point was measured to be two point five four so that's why this right over here is at two point five four when we've added about twenty nine point I forgot what the number was it was in the it was in I think the second part of this problem they said when he added close to thirty milliliters of that hydrochloric acid that one point two five molar hydrochloric acid solution that is when we hit our equivalence point and we see the pH right over there and then the half equivalence point well that's going to be when we've added half this amount so it's going to be a little bit less than fifteen and we in the last problem we figured out that that was going to be at a pH of four point seven seven so pH of four point seven seven is going to be something like right over there they said mark that with an X so half equivalence point we've added half the titrant there and we know the pH we figured that out in the last part of the problem and now we just need to graph we need to sketch the titration curve so let's see we keep we keep adding more and more hydrochloric acid hydrochloric acid it lowers lowers the pH we get to the half equivalence point and then actually we're going to we're going to start leveling off over here the reason why you level off is because you're going to have you're going to have more and more of the conjugate the conjugate acid there and so as you as you as you react with the conjugate base with more and more of the conjugate base the equilibrium between the conjugate base and the conjugate acid more of that acids going to go to conjugate base so you're gonna have a little bit of a buffering going on but at some point you have real did you have completely reacted with everything and you've you hit your equivalence point you hit your equivalence point and then and you've become much more acidic and it might look something it might look something like that let me see if I can do a little bit a little bit better a little bit better job so it would look something and we're obviously it's not going to be exactly right it's important we go through these three points and it would look something something like that so that's the equivalence point half equivalence point and then this is our initial pH
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