POST – LAB EXERCISE: 1. A solution sample may contain Ag+, Pb2+, and Hg22+ ions. After the addition of 6 M HCl, a white precipitate forms. The precipitate was partially soluble in hot water and the solid residue dissolves when 6M NH3 is added but no precipitate was formed. Answer the following questions based on the information provided above and justify your answer next to each question. a. Which of the ions are present in the solution sample? b. Which of the ions are absent in the solution sample? c. Which of the ions remains undetected?