The pOH of a solution 5.50 M is 5.50. What is its hydroxide-ion concentration? 3.2 x 10-5 M 3.2 x 10-6 M a. b. d. 3.2 x 10-7 M e. 3.2 x 10-9 M The pOH of a 0.015 M ammonia solution is 3.28. What is its hydroxide-ion concentration? C