Question 1
Which metal sulfides can be precipitated from a solution that is 0.01 M in Mn
2+, Zn
2+, Pb
2+ and Cu
2+ and 0.10 M in H
2S at a pH of 0.50?
◦ CuS
◦ ZnS, PbS, CuS
◦ PbS, CuS
◦ MnS
Question 2
A solution may contain the following ions Ag
+, Cu
2+, Cd
2+, Mn
2+, Ni
2+ and Na
+. A white precipitate formed when 0.10 M NaCl was added and after this was removed the solution was treated with H
2S gas under acidic conditions and no precipitate formed. When the solution was made basic and again treated with H
2S gas a dark colored precipitate formed. If no further tests were made then what conclusions can you draw?
◦ possible ions present Ag
+, Mn
2+, Ni
2+, Na
+◦ possible ions present Ag
+, Cu
2+, Cd
2+, Na
+◦ possible ions present Ag
+, Mn
2+, Ni
2+◦ possible ions present Ag
+, Cu
2+, Cd
2+
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