What is the maximum concentration of Ag⁺ that can be added to a 0.00690 M solution of Na₂CO₃ before a precipitate will form? (Ksp for Ag₂CO₃ is 8.10 × 10⁻¹²)

In this lab, we will experimentally determine the titration curve for the titration of a weak acid solution against a strong base solution. The weak acid we will use is potassium hydrogen phthalate, KHP, its chemical structure is shown below. KHP is an ionic compound composed of a potassium cation K+ and a hydrogen phthalate anion HP–. HP– is a weak acid and upon dissolving in water, can lower the pH of the solution. (a)  Suggest the chemical reaction(s) when a solid sample of KHP is dissolved in water, writing out the chemical equations for them. (b)  Sketch the structure of KHP from above and circle the hydrogen atom that is responsible for its acidity. (c)  Calculate the pH of a solution made of 0.50 g of KHP and 50 mL of water. KHP has a molar mass of 204.2 g and at 25 °C has a pKa of 5.4.

What is the maximum concentration of Ni²⁺ that can be added to a 0.00290 M solution of Na₂CO₃ before a precipitate will form? (Ksp for NiCO₃ is 1.30 × 10⁻⁷)

Lead(II) nitrate is added slowly to a solution that is 0.0100 M in Cl− ions. Calculate the concentration of Pb2+ ions (in mol / L) required to initiate the precipitation of PbCl2. (Ksp for PbCl2 is 2.40 × 10−4.)