these are the correct answers but I don't understand how the molecule was matched to the curve. i understand Acetic Acid but how do you differentiate between HCL, aspartate, and Leucine?

Question 7. (10 pts, 2 pts. each) A. Put the name of the correct molecule on the matching titration curve (base was added): HCl (a strann nnidl notir arid (a weak acid), Leucine, Aspartate B. Using a figure in part A, what is the pKa of the amino group of aspartate? q.76 C. Using a figure in part A, What is the pH range where acetic acid is a good buffer? 3.76 to 5.76