Question 3 (1 point) What is the approximate pka of a weak acid HA if a solution 1.8 M HA and 0.9 M A-has a pH of 6.7? Your Answer: Answer Question 4 (1 point) A particular acid [HA-) with pka=5.64 is used to make a buffered solution with a pH of 5.28; the total salt concentration is 51 mM. How many millimoles of conjugate base [A-] were used? Hint: Use the Henderson-Hasselbalch equation and this equation [HA] + [A-] = 51 Your