In a lab we did potentiometric titrations with a mixture of NaCl/KI and AgNO3. We plotted a titration curve and found the 2 endpoints which indicate where I is and where Cl is. We are looking to find the concentration of both of the halides present, and we have the equation Eind=E0(of Ag+) + 0.0592log(aAg+). I know that the acitivty in this case is linear to the concentration but whenever I try to put my values into this equation I get an answer of 0. Any help in how to figure this out would be greatly appreciated. The values I obtained were endpoint 1 is at 2.3mL with Eind being 347.9mv, and endpoint 2 is at 34.23ml with Eind being -12.8mv.