1. Divide the ions below into 2 groups, those that tend to form soluble compounds and those that tend to form insoluble compounds.
(〖Pb〗^(+2), 〖Na〗^+, 〖Nh4〗^+, 〖Ag〗^+, 〖NO3〗^-, 〖OH〗^-, 〖Cl〗^-, 〖CO3〗^(-2), 〖PO4〗^(-3))
2. Suppose a student returned some unused lead nitrate to the container to the container marked “sodium nitrate”. What could the student do to get all the lead ions ”out” from the sodium nitrate?
3. A solution contains 〖Nh4〗^+ ions and 〖Ca〗^(+2) along with some anions. How would you separate 〖Nh4〗^+ ions from 〖Ca〗^(+2) ?
I don't understand all of your symbols; here is simplified set of solubility rules.
http://www.files.chem.vt.edu/RVGS/ACT/notes/solubility_rules.html
To separate Pb(NO3)2 I would saturate the solution with H2S to ppt all of the Pb as PbS, filter, boil the filtrate to remove H2S and evaporate the solvent.
#3. Look at the solubility rules.
Suppose a student returned some unused lead nitrate to the container to the container marked “sodium nitrate”. What could the student do to get all the lead ions ”out” from the sodium nitrate?
1. To determine which ions tend to form soluble compounds and which tend to form insoluble compounds, we can use solubility rules. These rules provide guidelines on which compounds are soluble and which are insoluble. Here's how we can use the solubility rules to categorize the given ions:
a) Soluble compounds: Ions that tend to form soluble compounds include Na+, NH4+, NO3-, and OH-.
- Na+ (sodium ion) and NH4+ (ammonium ion) are alkali metal and ammonium ions respectively, which are generally soluble in water and most other solvents.
- NO3- (nitrate ion) is also soluble in water, as nitrates are generally soluble.
b) Insoluble compounds: Ions that tend to form insoluble compounds include Pb+2, Ag+, Cl-, CO3-2, and PO4-3.
- Pb+2 (lead ion) and Ag+ (silver ion) tend to form insoluble compounds in water, except when paired with nitrate (NO3-) or acetate (C2H3O2-) ions.
- Cl- (chloride ion) is typically soluble, but it forms insoluble compounds when paired with Ag+ or Pb+2 ions.
- CO3-2 (carbonate ion) and PO4-3 (phosphate ion) also tend to form insoluble compounds in water.
Therefore, the ions can be divided into the following two groups:
Group 1 (tend to form soluble compounds): Na+, NH4+, NO3-, OH-
Group 2 (tend to form insoluble compounds): Pb+2, Ag+, Cl-, CO3-2, PO4-3
2. If a student accidentally returns lead nitrate to a container labeled as sodium nitrate, which means there are now lead ions in the sodium nitrate, one way to remove the lead ions is through precipitation. Here's what the student can do:
- First, the student needs to add a suitable reagent that will react with the lead ions to form an insoluble precipitate. A common reagent for this purpose is sodium chloride (NaCl).
- The student should add a solution of sodium chloride to the sodium nitrate container. The chloride ions in the sodium chloride solution will react with the lead ions to form lead chloride (PbCl2), which is insoluble and will precipitate out of the solution.
- After adding the sodium chloride solution, the student should allow the mixture to settle. The lead chloride precipitate will gradually settle at the bottom of the container.
- Finally, the student can carefully decant (pour off) the supernatant liquid above the settled precipitate, leaving behind the lead chloride at the bottom of the container. This process separates the lead ions from the sodium nitrate solution.
3. To separate NH4+ ions from Ca+2 ions in a solution, you can utilize the difference in their solubilities and the formation of different compounds. Here's a possible separation method:
- One of the common compounds containing NH4+ ions is NH4Cl (ammonium chloride). Ammonium chloride is soluble in water and can form a solution.
- Calcium ions (Ca+2) can form insoluble compounds with various anions, such as carbonate (CO3-2), phosphate (PO4-3), and oxalate (C2O4-2). To separate NH4+ ions from Ca+2 ions, you can introduce one of these anions to the solution.
- For example, you can add a solution containing carbonate ions (CO3-2), such as sodium carbonate (Na2CO3), to the solution. This will cause the formation of an insoluble precipitate of calcium carbonate (CaCO3), while the NH4+ ions will remain in the solution.
- After adding the carbonate solution, you can let the mixture settle or use filtration to separate the insoluble precipitate of calcium carbonate from the solution containing NH4+ ions.
- Finally, you can recover the NH4+ ions from the solution by evaporating the solvent (water). As NH4Cl is soluble in water, you can obtain solid NH4Cl by evaporating the water from the solution.
By following this method, you can separate NH4+ ions from Ca+2 ions in the solution.