2. what solution can you add to each of the following cation mixtures to precipitate one cation while keeping the other cation in sloution? write complete and net ionic equations for thr precipitation reactons that occur.
a) sr+2 (aq) anf Hg+2 (aq)
b) ca+2 (aq) and NH4+ (aq)
c) Ba+2 (aq) and Mg+2 (aq)
d) Ag+ (aq) and Zn+2 (aq)
a) To precipitate Sr^2+ while keeping Hg^2+ in solution, we can add a solution of dilute sulfuric acid (H2SO4) because SrSO4 is insoluble while HgSO4 is soluble. The complete ionic equation is:
Sr^2+(aq) + SO4^2-(aq) + 2H+(aq) + 2Hg^2+(aq) → SrSO4(s) + 2H2O(l) + 2Hg^2+(aq)
The net ionic equation is:
Sr^2+(aq) + SO4^2-(aq) → SrSO4(s)
b) To precipitate Ca^2+ while keeping NH4+ in solution, we can add a solution of sodium carbonate (Na2CO3) because CaCO3 is insoluble while NH4+ does not form a precipitate with Na2CO3. The complete ionic equation is:
Ca^2+(aq) + CO3^2-(aq) + 2NH4+(aq) + 2Na+(aq) → CaCO3(s) + 2NH4+(aq) + 2Na+(aq)
The net ionic equation is:
Ca^2+(aq) + CO3^2-(aq) → CaCO3(s)
c) To precipitate Ba^2+ while keeping Mg^2+ in solution, we can add a solution of sodium sulfate (Na2SO4) because BaSO4 is insoluble while Mg^2+ does not form a precipitate with Na2SO4. The complete ionic equation is:
Ba^2+(aq) + SO4^2-(aq) + 2Mg^2+(aq) + 2Na+(aq) → BaSO4(s) + 2Mg^2+(aq) + 2Na+(aq)
The net ionic equation is:
Ba^2+(aq) + SO4^2-(aq) → BaSO4(s)
d) To precipitate Ag+ while keeping Zn^2+ in solution, we can add a solution of hydrochloric acid (HCl) because AgCl is insoluble while Zn^2+ does not form a precipitate with HCl. The complete ionic equation is:
Ag+(aq) + Cl-(aq) + Zn^2+(aq) + 2H+(aq) → AgCl(s) + Zn^2+(aq) + 2H+(aq)
The net ionic equation is:
Ag+(aq) + Cl-(aq) → AgCl(s)
To determine the solution that can be added to each cation mixture to precipitate one cation while keeping the other cation in solution, we need to consider the solubility rules of common ionic compounds. These rules provide guidelines on which compounds are soluble and which are insoluble in water.
a) For the mixture of Sr+2 (aq) and Hg+2 (aq):
According to the solubility rules, most sulfates (SO4^-2) are insoluble except for certain exceptions. So, to precipitate Sr+2 while keeping Hg+2 in solution, we can add a sulfate solution (SO4^-2) to the mixture.
The complete ionic equation for the precipitation reaction would be:
Sr+2 (aq) + SO4^-2 (aq) -> SrSO4 (s)
The net ionic equation would be:
Sr+2 (aq) + SO4^-2 (aq) -> SrSO4 (s)
b) For the mixture of Ca+2 (aq) and NH4+ (aq):
According to the solubility rules, most sulfides (S^-2) are insoluble except for certain exceptions. So, to precipitate Ca+2 while keeping NH4+ in solution, we can add a sulfide solution (S^-2) to the mixture.
The complete ionic equation for the precipitation reaction would be:
Ca+2 (aq) + S^-2 (aq) -> CaS (s)
The net ionic equation would be:
Ca+2 (aq) + S^-2 (aq) -> CaS (s)
c) For the mixture of Ba+2 (aq) and Mg+2 (aq):
According to the solubility rules, most carbonates (CO3^-2) are insoluble except for certain exceptions. So, to precipitate Ba+2 while keeping Mg+2 in solution, we can add a carbonate solution (CO3^-2) to the mixture.
The complete ionic equation for the precipitation reaction would be:
Ba+2 (aq) + CO3^-2 (aq) -> BaCO3 (s)
The net ionic equation would be:
Ba+2 (aq) + CO3^-2 (aq) -> BaCO3 (s)
d) For the mixture of Ag+ (aq) and Zn+2 (aq):
According to the solubility rules, most chlorides (Cl^-) are soluble except for certain exceptions. So, to precipitate Ag+ while keeping Zn+2 in solution, we can add a chloride solution (Cl^-) to the mixture.
The complete ionic equation for the precipitation reaction would be:
Ag+ (aq) + Cl^- (aq) -> AgCl (s)
The net ionic equation would be:
Ag+ (aq) + Cl^- (aq) -> AgCl (s)
It is important to note that these solubility rules serve as general guidelines, and there may be exceptions or additional factors to consider in specific cases. Always consult reliable sources or references for accurate information on solubility and precipitation reactions.
There is no way you can learn this without doing it the hard way. Here is a solubility chart that may help you get started. I will start one of them, c, for you.
http://www.files.chem.vt.edu/RVGS/ACT/notes/solubility_rules.html
Look at the solubility rules. The sulfates of Ba, Sr, and Ca ion are insoluble while those of Mg are soluble. (Ca is not all that insoluble). So we can add Na2SO4 to the solution and BaSO4 will ppt as a white solid. You can write the full equation. the net ionic equation is
Ba^2+(aq) + SO4^=(aq) ==> BaSO4(s)