Solubility        Quiz #7            Common Ion Effect

 

1.         Consider the following equilibrium: CaCO3(s)   ⇄ Ca2+(aq) +CO32-(aq)

            Which of the following reagents, when added to the equilibrium system, would cause more CaCO3 to dissolve?

            A.        KNO3(s)

            B.        CaCO3(s)

            C.        H2C2O4(s)

            D.        Na2CO3(s)

 

2.         A solution contains a mixture of SO42- and S2-. Which of the following cations could be used to remove only the SO42- from the solution by             precipitation?

               A.        K+

            B.        Sr2+

            C.        Pb2+

            D.        Cu2+

 

3.         Consider the following solubility equilibrium: MgCO3(s)⇄ Mg2+(aq) + CO32-(aq)

            The addition of which of the following substances would decrease the solubility of MgCO3?

            A.        H2O

            B.        NaCl

            C.        NaOH

            D.        Na2CO3

 

4.         A student could precipitate silver chloride from a saturated solution of silver chloride by adding

            A.        water

            B.        sodium iodide

            C.        sodium nitrate

            D.        sodium chloride

 

5.         The greatest mass of solid SnS will dissolve in 1.0 L of

            A.        H2O

            B.        0.10 M MgS

            C.        0.10 M (NH4)2S

            D.        0.10 M Sn(NO3)2

 

6.         Magnesium carbonate would be the most soluble in a solution of

            A.        MgCl2

            B.        NaNO3

            C.        Na2CO3

            D.        Mg(NO3)2

 

7.         Sodium iodide is added to a saturated solution of lead (II) iodide. The net change is

A.        [I-] increases and [Pb2+] increases

            B.        [I-] decreases and [Pb2+] decreases    

            C.        [I-] increases and [Pb2+] decreases

            D.        [I-] decreases and [Pb2+] increases

 

8.         Consider the following equilibrium: Pbl2(s) + heat ⇄ Pb2+(aq)  +  2I-(aq)

            Which of the following changes would result in more Pbl2 dissolving?

            A.        Adding more Pbl2

            B.        Increasing the pressure

            C.        Adding some Pb(NO3)2

            D.        Increasing the temperature

 

9.         Consider the following equilibrium: AgCl(s) ⇄ Ag+(aq) + Cl-(aq)

            Sodium chloride is added to a saturated solution of AgCl. The amount of solid AgCl will

            A.        increase as the equilibrium shifts to the left

            B.        decrease as the equilibrium shifts to the left

            C.        increase as the equilibrium shifts to the right

            D.        decrease as the equilibrium shifts to the right

 

 

 10.      Consider the following equilibrium: NH4Cl(s) + energy ⇄ NH+4(aq) +   Cl-(aq)    

            Which of the following will increase the solubility of ammonium chloride?

 

            A.        Stirring the solution

            B.        Adding more water

            C.        Adding more NH4Cl(s)

            D.        Increasing the temperature

 

 

11.       Which of the following substances will have the least effect on the equilibrium in a saturated solution of PbBr2(s)?

            A.        HI

            B.        Na2S

            C.        KNO3

            D.        Pb(NO3)2

 

12.       Which of the following substances will have the greatest effect on the equilibrium in a saturated solution of PbBr2(s)?

            A.        1.0 M Pb(NO3)2

            B.        1.0 MNaBr

            C.        1.0 M CaBr2

            D.        1.0 M AlBr3

 

13.       Which compound will have the lowest solubility?

            A.        BeS

            B.        FeS

            C.        ZnS

            D.        Cs2S

 

14.       Which compound will have the highest solubility?

            A.        CuS

            B.        FeS

            C.        ZnS

            D.        Cs2S

 

15.       Which anion would be most effective in removing the cations (Mg2+ and Ca2+) that are responsible for hard water?

            A.        S2-

            B.        Cl-

            C.        PO43-

            D.        SO42-

 

16.       Which of the following ions could be used in the lowest concentration to remove Ag+ ions from a polluted water sample?

            A.        I-

            B.        Br-

            C.        BrO3-

            D.        CO32-

 

17.       What will be the effect of adding some solid AgNO3 to a saturated solution of AgCl ?

            A.        The AgNO3 will not dissolve.

            B.        More solid AgCl will dissolve.

            C.        More solid AgCl will be produced.

            D.        There will be no effect on AgCl equilibrium.

 

18.       An experiment is conducted to identify an unknown cation that is present in each of four beakers. The following chemicals are added to an             unknown solution     containing one cation.

            RbNO3             (NH4)2S           MnSO4 Na2CO3

            no ppt              ppt                   no ppt              ppt

            Which of the following could be the unknown cation?

            A.        Ag+

            B.        Fe3+

            C.        Ba2+

            D.        Be2+

 

19.       An equal number of moles of Na2CO3 is added to four different 100.mL samples.

            Sample 1         Sample 2         Sample 3         Sample 4        

            0.50 M Ba2+     0.50 M Ca 2+      0.50 M Mg2+      0.50 M Sr2+

            A precipitate forms in only one of the samples.  Identify the cation which is present in the precipitate.

            A.        Ba2+

            B.        Ca2+

            C.        Mg2+

            D.        Sr2+

 

20.       An equal number of moles of Na2CO3 is added to four different samples that contain the cations below in low concentration.

            Sample 1         Sample 2         Sample 3         Sample 4        

            Ba2+                 Ca2+                   Mg2+                   Sr2+

            A precipitate forms in three of the samples.  Identify the cation which is present in sample that does not precipitate.

            A.        Ba2+

            B.        Ca2+

            C.        Mg2+

            D.        Sr2+

 

21.       Consider the following equilibrium:   Mg(OH)2(s)  ⇌  Mg2+  +  2OH-

            Adding which of the following would cause the solid to dissolve?

            A.        HCl

            B.        KOH

            C.        Mg(OH)2

            D.        Mg(NO3)2

 

22.       Consider the following equilibrium:   Mg(OH)2(s)  ⇌  Mg2+  +  2OH-

            Adding which of the following would cause the most solid to precipitate?

            A.       1.0 M HCl

            B.       1.0 M KOH

            C.       1.0 M Sr(OH)2

            D.       1.0 M Mg(NO3)2

 

23.       When equal volumes of 0.40 M Ca(NO3)2 and 0.40 M  Na2SO4are mixed together,

            A.        a precipitate forms and the Trial Ksp would be less than Ksp.

            B.        no precipitate forms and the Trial Ksp would be less than Ksp.

            C.        a precipitate forms and the Trial Ksp would be greater than Ksp.

            D.        no precipitate forms and the Trial Ksp would be greater than Ksp.

 

24.       When equal volumes of 0.002 M Ca(NO3)2 and 0.002 M  Na2SO4are mixed together,

            A.        a precipitate forms and the Trial Ksp is less than Ksp.

            B.        no precipitate forms and the Trial Ksp is less than Ksp.

            C.        a precipitate forms and the Trial Ksp is greater than Ksp.

            D.        no precipitate forms and the Trial Ksp is greater than Ksp.

 

25.       When equal volumes of 0.02 M Ca(NO3)2 and 0.02 M  Na2SO4are mixed together,

            A.        a precipitate forms and the Trial Ksp is less than Ksp.

            B.        no precipitate forms and the Trial Ksp is less than Ksp.

            C.        a precipitate forms and the Trial Ksp is greater than Ksp.

            D.        no precipitate forms and the Trial Ksp is greater than Ksp.

 

26.       Which of the following is commonly used to describe the solubility of a compound?

            A.        mass of solute / moles of solute

            B.        moles of solution / mass of solute

            C.        mass of solute / volume of solution

            D.        mass of solution / volume of solute