Now when it comes to polyportic buffers, we typically are dealing with Tri protic species. Because of this, we're going to say it deals with the presence of three equivalence points and Henderson Hasselbeck equations as a result of three K_A values. Here we're going to say the relationship between the equivalence points and Henderson Hasselbeck equations are shown as.

So first we're going to talk about the dissociation steps here. H₃A is the generic form of a triprotic acid. So here it has all of its H⁺ ions in its possession. So this is the acidic form. So now here we're talking about giving away the first H, so that B K_A1. Doing that gives us H₂A^-. This would represent our intermediate form 1 that can continue to donate in H or donates a second H⁺ so that B K_A2. That gives us HA^2-, which is our intermediate form, 2. This one has an H⁺, so it too can donate an H, which will deal with K_A3. Doing that gives us A^3-, which is the basic form.

Now we could also go the opposite way, where the basic form gained its first H⁺ to create the intermediate form 2. Gaining your first H is K_B1. The intermediate form 2 can gain another H⁺, so that would be K_B2 to give us intermediate form one. And then finally the intermediate form one can gain that last H⁺ it needs to recreate the acidic form. So that'd be K_B3. We'd see here that these two are grouped together, these two are grouped together, these two are grouped together, so that segues into our K_AK_B equations.

Here we'd say K_A1 times K_B3 equals K_W, K_A2 times K_B2 equals K_W, and K_A3 times K_B1 equals K_W. From there, we could talk about the different types of Henderson Hasselbeck equation. So the first one deals with the acidic form and the intermediate form 1. We're talking about the first K_A here. So this would be pK_A1 plus. Now all of these are based on this simpler idea of Henderson Hasselbeck equation is pH equals pK_A plus log of base over acid. The base is the one with one less hydrogen. The acid is the one that has one extra hydrogen.

So here it D be plus log of base over assets, so that would be H₂A^- over H₃A. The next one deals with the two intermediate forms, so they're connected by K_A2. So this would be pK_A2 plus log of base over assets. So that would be HA^2-, / H₂A^-. And then finally here intermediate form 2 and basic form give us the last Henderson Hasselbeck equation. We're dealing with K_A3 in this regard. So this would be pH equals pK_A3 plus A^3-, / HA^2-. So these would be the three Henderson Hasselbeck equation associated with a typical tripodic buffer.