3) The pKa of the buffer system we are using this week, phosphate buffer, is 6.85. Your instructors will assign your group a pH other than the pK in the useful buffer range (pka + 1), and solve for the ratio of [A-] to (HA) in the space below. You MUST show your math. 4) You are going to need to make 100mL of solution containing 0.1 M final concentration of the buffer. You will have to use algebra to solve for the final concentrations of each component. Let [A] =y and let (HA) = 0.1 - y. Solve for y. Then solve for each concentration using substitution. Do so in the space below. 5) Now that you have that information, our overall goal is to determine how much of each of the solids to weigh out on the balance. A = K2HPO4, and has a molar mass of 174.18 g/mol. Calculate the number of grams of A-needed