Now let's take a look at the opposite print. Here, our weak base will be our titrate. We're starting at a pH above 7, and we're adding strong acid to it. Strong acid will be our titrant. Now because we're starting out with a base, we'd expect our pH to be greater than 7 initially and it decreases gradually with acid. That's because initially there's going to be a quick drop in pH, but then it's going to kind of level off because in this highlighted region, a buffer region has been created.
So this is going to resist additional drop, steady clear drop in pH. It's going to gradually slow down. It's still going to be decreasing, just not at the same fast rate. Now here, what's the pH at the equivalence point? Remember, we have a weak species and a strong species. The strong species will dictate where the pH will be at the equivalence point. Because it's a strong acid, it wants an acidic pH, so it wants the pH to be less than seven at the equivalence point. Here we can see that the equivalence point is around a pH of five.
Now after the equivalence point, so after the red dot, we can see that the weak base is neutralized, but we still keep adding strong acid. So there's going to be some excess strong acid remaining. Eventually it's going to level off and plateau. And when again, when it comes to weak and strong, whatever is strong will dictate what kind of pH we will have at the equivalence point. In the first one, since we had a strong base, the pH was above 7 at the equivalence point. In this one, the acid is what's strong. So we're going to have a pH less than seven at the equivalence point.
So keep this in mind when looking at these two types of titration curves.