6.(1 pt) Dr. Stevens has 100 mL of a 0.10 M solution of a weak acid with a pka of 6.3. She adds 6,0 mL of 1.0 M HCI, which changes the pH to 5.7. What was the pH of the original solution? 17.(1) Calculme the concentration of noetic acid (oku - 4,76) and sodium acetate necessary to prepare a 0.2 M buffer solution at p 5.0