Is the above graph is of a dibasic or monobasic acid? There is slight hint of it being of dibasic around 15. But is it enough to conclude ? I am confused.
As I understand it, if the data is absolutely correct, the curve should not change direction of curvature in that manner if it is monibasic. Each time it's double differentiation changes signs 2 times, I think it passes an equivalence point no matter how shallow it is. It should be a dibasic acid. You can get a function of [H+] using equilibrium constant (assume it to be monobasic) and taking x as moles of naoh added in other words, the "initial" moles of salt x is and "initial" moles of acid is a-x, a is the moles of acid we started with.By "initial" I mean the moles before equilibrium. You would get a quadratic equation, see at how many times sign of double differentiation of -log([H+]) wrt x changes for any value of x. Here is oxalic acid's curve.