Quiz 1 - Solubility and Precipitation Reactions | Solubility and Precipitation Reactions
General Chemistry 3 - Quiz 1 - Solubility and Precipitation Reactions
What is the expression for the solubility product constant (Ksp) for calcium fluoride (CaF2)?
The solubility product constant, Ksp, for CaF2 is based on the dissociation: CaF2 ⇌ Ca2+ + 2 F−.
Which of the following best describes fractional precipitation?
Fractional precipitation involves selectively precipitating one ion while leaving other ions in solution, based on differences in solubility.
What is the solubility of AgCl in water at 25°C if Ksp for AgCl is 1.8 x 10−10?
Since AgCl dissociates as AgCl ⇌ Ag+ + Cl−, the Ksp expression is Ksp = s2.
Solving for s = = 1.3 x 10-5 M
Which factor would decrease the solubility of Ca(OH)2 in water?
Adding CaCl2 increases the concentration of Ca2+ ions, shifting the equilibrium to the left and decreasing the solubility of Ca(OH)2.
What would happen to the solubility of CaF2 if the solution were acidified?
Acidifying the solution adds H+ ions, which react with F- ions to form HF, reducing F- concentration and increasing the solubility of CaF2.
What is the purpose of qualitative analysis in the context of precipitation reactions?
Qualitative analysis uses precipitation reactions to detect specific ions in a sample by observing the formation of characteristic precipitates.
Which of the following is true about the common ion effect?
The common ion effect decreases the solubility of an ionic compound by shifting the equilibrium toward the undissociated form when an ion in common with the solute is added.
If equal volumes of 0.01 M AgNO3 and 0.01 M NaCl are mixed, will a precipitate form? (Ksp of AgCl = 1.8 x 10−10)
Mixing the solutions gives [Ag+] = [Cl−] = 0.005 M
Q = [Ag+][Cl−] = (0.005)(0.005) = 2.5 x 10−8, which is greater than Ksp, so a precipitate will form.
Which of the following metal cations will precipitate as a chloride when dilute HCl is added to the solution?
Group 1 cations, which include Ag+, Pb2+, and Hg22+, precipitate as chlorides when dilute HCl is added. These cations form insoluble chlorides, allowing them to be selectively separated from other groups of cations in qualitative analysis.
Which reagent would you add to a solution to precipitate Group 2 metal cations selectively?
Group 2 cations, such as Pb2+, Cu2+, and Bi3+, precipitate as sulfides in acidic conditions when hydrogen sulfide is added. This allows these cations to be separated from others based on their solubility as sulfides.