This one stumped me alot...
Aqueous solutions of a compound did not form precipitates with Cl-, Br-, I-, SO4 2-, CO3 2-, PO4 3-, OH-, or S 2-. This highly water-soluble compound produced the foul-smelling gas H2S when the solution was acidified. This compund is __?__.
a. Pb(NO3)2
b. (NH4)2S
c. KBr
d. Li2CO3
e. AgNO3
(NH4)2S
In order to produce H2S, you MUST have a sulfide compound. You have only one listed. Can't be anything else. It also turns out that NH4X is soluble for that entire list you typed in which is a second check.
To determine the compound, we need to analyze the clues provided.
First, the compound is highly water-soluble, which eliminates options b (NH4)2S, c KBr, d Li2CO3, and e AgNO3 since these compounds are not highly water-soluble.
Next, we know that none of the listed anions (Cl-, Br-, I-, SO4 2-, CO3 2-, PO4 3-, OH-, or S2-) form precipitates with the compound, ruling out options a Pb(NO3)2 (which forms a precipitate with Cl-, Br-, and I-) and c KBr (which forms a precipitate with AgNO3).
Lastly, the compound produces the foul-smelling gas H2S when the solution is acidified. This indicates that the compound contains sulfur (S), so our final answer is a. Pb(NO3)2.
To arrive at this answer, you need to have a good understanding of solubility rules and be able to identify the formation of a specific gas from the reaction.