Ag2S is an insoluable black solid. Would more solid dissolve, or precipitate once the following are added to the solution.
1. KS-----I know [S] increases, shift to reactants side, precipitate
2. HClO
3. LiOH
4. NH4OH
First, note the correct spelling (and it may affect your pronunciation, too) of insoluble.
Ag2S ==> 2Ag^+ + S^2-
1. right. K2S increases S, shifts to the left and more ppt forms.
2. HClO. Increases H^+ which reacts with S^2- (as in S^2- + H^+ ==> HS^-) and you should recognize HS^- as the intermediate in H2S which is a weak acid. Therefore, adding H^+ DECREASES S^2- due to the formation of HS^- and more Ag2S will dissolve (shift to the right).
3. LiOH. You can go through the reasoning but obviously this is the opposite of 2.
4. NH4OH. Technically, NH4OH doesn't exist, it really is NH3 + H2O. At any rate, NH3 + Ag^+ forms Ag(NH3)2^+, that decreases the Ag^+ and that shifts the reaction to the right and more Ag2S dissolves.
To determine whether more Ag2S will dissolve or precipitate when the given substances are added to the solution, we need to consider the solubility of Ag2S and the reaction that occurs between the added substance and Ag2S.
1. KS (potassium sulfide): When KS is added to the solution, it increases the concentration of sulfide ions ([S]), which can react with Ag+ ions from Ag2S to form Ag2S precipitate (s). The balanced equation is:
Ag2S (s) + S2- → 2Ag2S (s)
Since [S] increases, the equilibrium will shift to the left (reactants side), favoring the formation of more Ag2S precipitate. Therefore, the addition of KS will cause more solid to precipitate.
2. HClO (hypochlorous acid): HClO will ionize in water to produce H+ and ClO- ions. However, neither of these ions will react with Ag2S to form a precipitate. Therefore, the addition of HClO will not affect the solubility of Ag2S, and no additional solid will dissolve or precipitate.
3. LiOH (lithium hydroxide): When LiOH is added, it will dissociate into Li+ and OH- ions. However, neither of these ions will react with Ag2S to form a precipitate. Therefore, the addition of LiOH will not affect the solubility of Ag2S, and no additional solid will dissolve or precipitate.
4. NH4OH (ammonium hydroxide): NH4OH will dissociate in water to produce NH4+ and OH- ions. The OH- ions can react with Ag+ ions from Ag2S to form Ag2O(s) and H2O. The balanced equation is:
Ag2S (s) + 2OH- → Ag2O (s) + H2S (g)
Since the OH- ions will react with Ag2S, the addition of NH4OH will cause some of the solid Ag2S to dissolve and form Ag2O precipitate instead. Therefore, more solid Ag2S will dissolve when NH4OH is added.
In summary, more solid will precipitate when KS is added, and more solid will dissolve when NH4OH is added. The addition of HClO and LiOH will not affect the solubility of Ag2S.