1. Acidic Buffer Solution: An acidic buffer solution is a solution that resists changes in its pH when small amounts of acid or base are added. It is made by mixing a weak acid and its conjugate base (or a salt of the weak acid) in appropriate concentrations. The buffer maintains a relatively constant pH even when acidic or basic substances are introduced. A common example of an acidic buffer is a solution of acetic acid (CH COOH) and sodium acetate (CH COONa). 2. Relationship between Solubility and Solubility Product for PbI : The solubility product for lead iodide (PbI ) is a constant at a given temperature and describes the equilibrium between solid PbI and its ions in solution. The dissociation of PbI in water can be represented as: The solubility product expression is: Let the solubility of PbI be mol/L. At equilibrium, the concentration of Pb will be , and the concentration of I will be . Therefore, the solubility product can be written as: So, the solubility of PbI is related to the solubility product by: Thus, the solubility of PbI is the cube root of divided by 4.