University of South Florida CHM 2046 1)What is the molar solubility of MgF2 in a 0

Question

University of South Florida

CHM 2046

1)What is the molar solubility of MgF2 in a 0.45 M NaF solution? For MgF2, Ksp = 8.4 ´ 10^–8. A) 1.0 ´ 10^–7 M

B) 1.4 ´ 10^–4 M

C) 1.9 ´ 10^–7 M

D) 7.1 ´ 10^–4 M

E) 4.1 ´ 10^–7 M

Ksp for PbF2 is 4.0 ´10^–8. If a 0.034 M NaF solution is saturated with PbF2, what is [Pb²⁺] in solution?

A) 4.6 ´ 10^–11 M

B) 1.4 ´ 10^–9 M

C) 1.2 ´ 10^–6 M

D) 1.0 ´ 10^–3 M

E) 3.5 ´ 10^–5 M

The solubility of La(IO3)3 in a 0.62 M KIO3 solution is 1.0 ´10^–7 mol/L. Calculate Ksp for La(IO3)3. A) 6.2 ´ 10^–8

B) 2.4 ´ 10^–22

C) 2.4 ´ 10^–1

D) 2.4 ´ 10^–8

E) none of these

Which of the following, when added to a saturated solution of AgCl, will cause a decrease in the molar concentration of Ag⁺ relative to the original solution?

HCl(g)
AgCl(s)
MgCl2(s)

1. 1 only
2. 2 only
3. 3 only
4. 1 and 3
5. 1, 2, and 3

How many moles of CaF2 will dissolve in 3.0 L of 0.051 M NaF solution? (Ksp for CaF2 = 4.0 ´ 10^–11) A) 2.6 ´ 10^–10

B) 1.5 ´ 10^–8

C) 4.6 ´ 10^–8

D) 5.1 ´ 10^–9

E) none of these

Which of Figures I–IV represent(s) the result of mixing aqueous solutions of Na2S and NiCl2 in which the ion product Qc > Ksp for the insoluble product? (C = cation, A = anion)

1. both I and II
2. only I
3. only II
4. only III
5. only IV

Which Figures I–IV represent(s) the result of mixing aqueous solutions of NaOH and CuCl2 in which the ion product Qc > Ksp for the insoluble product? (C = cation, A = anion)

1. only II
2. both I and II
3. only IV
4. only I
5. only III

For which of the following will precipitation be expected?
1. Qc < Ksp
2. Qc = 1
3. Qc = Ksp
4. Qc > Ksp
5. Ksp = 1

Which of the following will apply to a saturated solution of an ionic compound?
1. Qc < Ksp
2. Qc > Ksp
3. Qc = Ksp
4. Ksp = 1
5. Qc = 1

Suppose 50.00 mL of 2.0 ´ 10^–6 M Fe(NO3)3 is added to 50.00 mL of 2.0 ´10^–4 M KIO3. Which of the following statements is true? For Fe(IO3)3, Ksp = 1.0 ´ 10^–14.
1. A precipitate forms because Qc > Ksp.
2. A precipitate forms because Qc < Ksp.
3. No precipitate forms because Qc < Ksp.
4. No precipitate forms because Qc = Ksp.
5. No precipitate forms because Qc > Ksp.

To 1.0 L of water, 3.0 ´ 10^–6 mol of Pb(NO3)2, 4.0 ´ 10^–6 mol of K2CrO4, and 1.0 mol of NaCl are added. What will happen?

Salt Ksp

PbCrO4 1.8 ´ 10^–14

PbCl2 1.6 ´ 10^–5

1. A precipitate of KCl will form.
2. A precipitate of PbCrO4 will form.
3. A precipitate of PbCl2 will form.
4. No precipitate will form.
5. Both a precipitate of PbCl2 and a precipitate of PbCrO4 will form.

What is the maximum Sr²⁺ concentration possible in a solution that has a 6.3 ×10- 5 M sulfide-ion concentration without precipitating strontium sulfate? For SrSO4, Ksp = 2.5 ´ 10^–7.

A) 1.6 ×10- 10 M

B) 1.6 ×10- 11 M

C) 4.0 ×10- 3 M

D) 6.3 ×10- 5 M

E) 2.5 ×102 M

What will happen if 0.1 mol of solid silver(I) nitrate is added to 1.0 L of a saturated solution of silver(I) chromate? For Ag2CrO4, Ksp = 2.4 ´ 10^–12.
1. The AgNO3 will settle to the bottom without dissolving.

4

The concentration of CrO ^2– will increase.

1. Some Ag2CrO4 will precipitate.
2. Nothing will happen.
3. The concentration of Ag⁺ in solution will not change.

A 4.0 ´ 10^–4 M solution of MnSO4 is gradually made more basic by adding NaOH. At what pH will manganese(II) hydroxide begin to precipitate? For Mn(OH)2, Ksp = 2.0 ´ 10^–13.

A) 4.70

B) 9.57

C) 4.65

D) 9.35

E) 9.30

What is the minimum concentration of Cu²⁺ required to begin precipitating Cu(OH)2(s) in a solution of pH 10.77? For Cu(OH)2, Ksp = 2.6 ´ 10^–19.

A) 2.9 ´ 10^–4 M

B) 1.5 ´ 10^–8 M

C) 4.4 ´ 10^–16 M

D) 7.5 ´ 10^–13 M

E) 2.2 ´ 10^–21 M

What is the maximum hydroxide-ion concentration that a 0.027 M MgCl2 solution could have without causing the precipitation of Mg(OH)2? For Mg(OH)2, Ksp = 1.8 ´ 10^–11.

A) 4.2 ´ 10^–6

B) 1.7 ´ 10^–4

C) 1.2 ´ 10^–8

D) 6.7 ´ 10^–9

E) 2.6 ´ 10^–5

If 500 mL of 1.4 ´ 10^–6 M AgNO3 is mixed with 500 mL of 1.4 ´ 10^–6 M NaBr, what will occur? For AgBr,

Ksp = 5 ´ 10^–13.

1. Silver(I) bromide will precipitate.
2. The concentration of Ag⁺ will be 1.4 ´ 10^–6 M.
3. 7.0 ´ 10^–7 mol of AgBr will form.
4. No precipitation will occur.
5. Sodium bromide will precipitate.

Suppose 50.00 mL of a 1 ´ 10^–5 M solution of lead(II) nitrate is mixed with 50.00 mL of a 1 ´ 10^–6 solution of sodium phosphate. Which of the following statements is true? For lead(II) phosphate, Ksp = 1 ´ 10^–44.
1. A precipitate forms because Qc < Ksp.
2. No precipitate forms because Qc > Ksp.
3. A precipitate forms because Qc > Ksp.
4. No precipitate forms because Qc = Ksp.
5. No precipitate forms because Qc < Ksp.

If 270 mL of 1 ´ 10^–7 M AgNO3 is mixed with 270 mL of 1 ´ 10^–8 M NaI, what will occur? For AgI, Ksp = 8.3 ´ 10^–17.
1. Sodium nitrate will precipitate.
2. Silver(I) nitrate will precipitate.
3. Sodium iodide will precipitate.
4. Silver(I) iodide will precipitate.
5. No precipitate will form.

If 315 mL of 1 ´ 10^–4 M Ca(NO3)2 is mixed with 315 mL of 1 ´ 10^–4 M NaF, what will occur? For CaF2,

Ksp = 3.4 ´ 10^–11.

1. No precipitate will form.
2. Sodium nitrate will precipitate.
3. Calcium nitrate will precipitate.
4. Calcium fluoride will precipitate.
5. Sodium fluoride will precipitate.

If 270 mL of 1 ´ 10^–8 M Al(NO3)3 is mixed with 270 mL of 1 ´ 10^–8 M NaOH, what will occur? For Al(OH)3,

Ksp = 4.6 ´ 10^–33.

1. Aluminum hydroxide will precipitate.
2. Sodium hydroxide will precipitate.
3. Aluminum nitrate will precipitate.
4. Sodium nitrate will precipitate.
5. No precipitate will form.

What is the minimum mass of Na2CO3 that must be added to 24.6 mL of a 9.5 ´ 10^–4 M AgNO3 solution in order for precipitation to occur? For Ag2CO3, Ksp = 8.6 ´ 10^–12 .

A) 2.5 ´ 10^–3 g

B) 3.1 ´ 10^–4 g

C) 1.2 ´ 10^–3 g

D) 2.4 ´ 10^–8 g

E) 2.5 ´ 10^–5 g

What is the maximum volume of 4.9 ´ 10^–5 M K2CrO4 that, added to 17.0 mL of a solution that is 8.6 ´ 10^–5 M Ba(NO3)2 and 5.4 ´ 10^–6 M Pb(NO3)2, will precipitate PbCrO4 but not BaCrO4? For PbCrO4, Ksp = 1.8 ´ 10^–14, and for BaCrO4, Ksp = 1.2 ´ 10^–10.
1. 17 mL
2. 0.51 mL
3. 0.48 mL

D) 0.0012 mL

E) 7.7 mL

A solution is 0.010 M in each of Pb(NO3)2, Mn(NO3)2, and Zn(NO3)2. Solid NaOH is added until the pH of the solution is 8.50. Which of the following statements is true?

Salt Ksp

Pb(OH)2 1.4 ´ 10^–20

Mn(OH)2 2.0 ´ 10^–13

Zn(OH)2 2.1 ´ 10^–16

1. Only Mn(OH)2 will precipitate.
2. All three hydroxides will precipitate.
3. Only Pb(OH)2 will precipitate.
4. No precipitate will form.
5. Only Zn(OH)2 and Pb(OH)2 will precipitate.

3 sp 3 sp

What is the maximum concentration of carbonate ions that will precipitate BaCO3 but not MgCO3 from a solution that is 2.7 ×10- 3 M each in Mg²⁺ and Ba²⁺? For MgCO , K = 1.0 ´ 10^–5 and for BaCO , K = 2.6 ´ 10^–9.

A) 3.7 ×10- 3 M

B) 9.6 ×10- 7 M

C) 2.7 ×10- 8 M

D) 7.0 ×10- 12 M

E) 2.6 ´ 10^–14 M

Which of the following solutions should be added to a solution containing both copper(II) ions and silver(I) ions in order to precipitate only one of the ions?
1. HCl(aq)
2. H2S(aq)
3. HNO3(aq)
4. H2S(aq) + HCl(aq)
5. H2S(aq) + HNO3(aq)

For which pair of cations would the addition of dilute hydrobromic acid precipitate one but not the other?
1. Ag⁺ and Ca²⁺

2

Hg ²⁺ and Ag⁺

1. Ba²⁺ and Na⁺
2. Ca²⁺ and Ba²⁺
3. Pb²⁺ and Ag⁺

Sodium chloride is added slowly to a solution that is 0.010 M in Cu⁺, Ag⁺, and Au⁺. The Ksp values for the chloride salts are 1.9 ´ 10^–7, 1.6 ´ 10^–10, and 2.0 ´ 10^–13, respectively. Which compound will precipitate first?
1. AuCl(s)
2. All will precipitate at the same time.
3. It cannot be determined.
4. AgCl(s)
5. CuCl(s)

Solid KCN is added to a solution composed of 0.10 M Ag⁺ and 0.10 M Zn²⁺ just until a precipitate forms. What is the composition of this initial precipitate? AgCN Ksp = 2.2 ´ 10^-16 and Zn(CN)2 Ksp = 3 ´ 10^-16.
1. The precipitate is pure AgCN(s).
2. The precipitateis pure Zn(CN)2(s).
3. The precipitate is a mixture of AgCN(s) and Zn(CN)2(s).
4. The precipitate is a mixture of KCN(s) and AgCN(s).
5. The precipitate is a mixture of KCN(s) and Zn(CN)2(s).

6

Silver nitrate (AgNO3) is slowly added to a solution containing 0.100 M Br^- and 0.050 M FeCN ^4- until a precipitate just forms. What is the molar concentration of Ag⁺ just as the precipitate forms? AgBr Ksp = 5.0 ´ 10^-13 and Ag4FeCN6 Ksp = 8.5 ´ 10^-45.

A) 2.0 ´ 10^-11 M Ag⁺

B) 5.0 ´ 10^-12 M Ag⁺

C) 1.0 ´ 10^-11 M Ag⁺

D) 3.3 ´ 10^-12 M Ag⁺

E) 1.7 ´ 10^-43 M Ag⁺

A solution contains 0.018 mol each of I^–, Br^–, and Cl^–. When the solution is mixed with 200 mL of 0.24 M AgNO3, how much AgCl(s) precipitates out?

Ksp	AgI	= 1.5 ´ 10^–16
Ksp	AgBr	= 5.0 ´ 10^–13
Ksp	AgCl	= 1.6 ´ 10^–10
A) 5.0 g
B) 3.3 g
C) 2.6 g
D) 0.0 g
E) 1.7 g

The best explanation for the dissolution of ZnS in dilute HCl is that
1. the zinc ion is amphoteric.
2. the sulfide ion concentration is decreased by the formation of H2S.
3. the solubility product of ZnCl2 is less than that of ZnS.
4. the zinc ion concentration is decreased by the formation of a chloro complex.
5. the sulfide ion concentration is decreased by oxidation to sulfur.

You have two salts, AgX and AgY, with very similar Ksp values. You know that Ka for HX is much greater than Ka

for HY. Which statement will be true?

1. AgX and AgY are less soluble in acidic solution than in pure water.
2. AgX is more soluble in acidic solution.
3. AgX and AgY are equally soluble in acidic solution.
4. AgY is more soluble in acidic solution.
5. none of these

For which of the following salts would the addition of nitric acid increase its solubility?
1. AgI
2. AgNO3
3. AgCl
4. Ag2SO4
5. AgBr

Which of the following substances will increase the molar solubility of nickel(II) phosphate in a saturated solution?
1. AgCl
2. HNO3
3. KOH
4. AlPO4
5. Na3PO4

In which of the following solutions would CaC2O4 have the highest molar solubility?
1. 0.01 M Na2C2O4
2. 0.01 M NaCl
3. 0.01 M HCl

D) 0.01 M Ca(NO3)2

E) 0.01 M NaHC2O4

The figure below represents the results of adding a strong acid to a saturated solution of an ionic compound. Which of the following could be the ionic compound?

1. AgClO4
2. AgF
3. AgI
4. AgCl
5. AgBr

What is the best way to ensure complete precipitation of SnS from a saturated H2S solution?
1. Add a strong acid.
2. Add a weak acid.
3. Add a strong base.
4. Add a weak base.
5. Add more H2S.

Suppose hydrogen sulfide is added to a solution that is 0.10 M in Cu²⁺, Pb²⁺, and Ni²⁺ such that the concentration of H2S is 0.10 M. When the pH of the solution is adjusted to 1.00, a precipitate forms. What is the composition of the precipitate?

H2S(aq) + 2H2O(l) 2H3O⁺(aq) + S^2–(aq); Kc = 1.1 ´ 10^–20

Salt Ksp

CuS 6.0 ´ 10^–36

PbS 2.5 ´ 10^–27

NiS 3.0 ´ 10^–19

1. CuS only
2. PbS and NiS
3. CuS and PbS
4. NiS only
5. CuS, PbS, and NiS

Suppose hydrogen sulfide is added to a solution that is 0.0010 M in Fe²⁺, Cd²⁺, Co²⁺, and Mn²⁺ such that the concentration of H2S is 0.10 M. When the pH of the solution is adjusted to 3, a precipitate forms. What is the composition of the precipitate?

H2S(aq) + 2H2O(l) 2H3O⁺(aq) + S^2–(aq); Kc = 1.1 ´ 10^–20

Salt Ksp

FeS 6.0 ´ 10^–18

CdS 8.0 ´ 10^–27

CoS 4.0 ´ 10^–21

MnS 2.5 ´ 10^–10

1. CdS only
2. CdS, CoS, FeS, and MnS
3. CdS, CoS, and FeS
4. CdS and FeS
5. CdS and CoS

3 4 3 4

What is the value of the dissociation constant, Kd, for the complex ion Cd(NH ) ²⁺? For Cd(NH ) ²⁺, Kf = 1.0 ´ 10⁷. A) 1.0 ´ 10^–7

B) 2.5 ´ 10⁶

C) 1.0 ´ 10⁷

D) 5.6 ´ 10¹

E) 1.0 ´ 10^–7

Which of the following is not likely to form a complex ion with Al³⁺?

4

NH ⁺

1. NH3
2. OH^-
3. H2O
4. CH3NH2

Which of the following statements concerning amphoteric hydroxides is/are correct?

The amphoteric hydroxide of aluminum(III) is commercially used to separate aluminum(III) oxide from impurities in the aluminum ore bauxite.
Amphoteric hydroxides form soluble complex ions at high pH’s.

4

The amphoteric hydroxide, Zn(OH)2, can be precipitated by increasing the pH of a solution containing Zn²⁺(aq) or lowering the pH of a solution containing Zn(OH) ^2-.

1. 1 only
2. 2 only
3. 3 only
4. 1 and 2
5. 1, 2, and 3

3 4

3 f 3 4

Calculate the molar concentration of uncomplexed Zn²⁺(aq) in a solution that contains 0.22 mol of Zn(NH ) ²⁺ per liter and 0.3109 M NH at equilibrium. K for Zn(NH ) ²⁺ is 2.9 ×109 .

A) 8.1 ×10- 9 M

B) 2.4 ×10- 10 M

C) 1.2 ×108 M

D) 7.8 ×10- 10 M

E) 6.8 ×1010 M

2

f 2

Cyanide ion forms very stable complex ions with a variety of metal ions. What is the molar equilibrium concentration of uncomplexed Cu²⁺(aq) in a solution that initially contains 1.3 mol of Cu(CN) ^- per liter of solution . K for Cu(CN) ^- is 2.8 ×1016 .

A) 2.3 ×10- 6 M

B) 3.6 ×10- 6 M

C) 4.4 ×105 M

D) 3.4 ×10- 9 M

E) 1.2 ×10- 17 M

2

What is the molar equilibrium concentration of uncomplexed Ag⁺(aq) in a solution composed of 1.1 mol Ag(CN) ^-

f 2

dissolved in 1.00 L of 0.47 M NaCN. K for Ag(CN) ^- is 4.5 ×1010 .

A) 1.1 ×10- 10 M

B) 5.2 ×10- 11 M

C) 9.0 ×109 M

D) 2.4 ×10- 10 M

E) 1.1 ×10- 5 M

2 3

An aqueous solution of Ag(CN) ^- is made by combining 0.0100 moles AgNO with 1.00 mole NaCN and diluting to

1.000 L. What is the molar concentration of Ag⁺ in the solution?

2 f

Ag⁺(aq) + 2CN^–(aq) Ag(CN) ^–(aq); K = 5.6 ´ 10¹⁸ A) 1.9 ´ 10^-21 M

B) 5.3 ´ 10²⁰ M

C) 5.8 ´ 10¹⁶ M

D) 1.7 ´ 10^-17 M

E) 0.010 M

Suppose sodium hydroxide is added to a 0.0016 M solution of zinc nitrate such that the pH of the solution is 13.42. What is the equilibrium concentration of Zn²⁺?

Zn²⁺(aq) + 4OH^–(aq) Zn(OH)42–(aq); Kf = 2.8 ´ 10¹⁵ A) 2.2 ´ 10^–18 M

B) 1.6 ´ 10^–3 M

C) 6.6 ´ 10^–2 M

D) 1.2 ´ 10^–16 M

E) 2.2 ´ 10^–18 M

3 4

What is the concentration of Cd²⁺ in a 0.010 M Cd(NO3)2 solution that is also 1.0 M NH3? For Cd(NH ) ²⁺,

Kf = 1.0 ´ 10⁷.

A) 3.2 ´ 10^–5 M

B) 1.0 ´ 10^–9 M

C) 1.2 ´ 10^–9 M

D) 3.2 ´ 10^–4 M

E) 1.0 ´ 10^–2 M

Which of the following insoluble salts will dissolve upon reaction with excess ammonia?
1. BaSO4
2. CaCO3
3. PbSO4
4. HgS
5. AgCl

Which sparingly soluble salt will exhibit the highest solubility at low pH’s? A) PbS (Ksp = 2.5 ´ 10^-27)

B) MnS (Ksp = 2.5 ´ 10^-10)

C) HgS (Ksp = 1.6 ´ 10^-52)

D) NiS (Ksp = 3 ´ 10^-9)

E) ZnS (Ksp = 1.1 ´ 10^-21)

The figure below represents the results of adding NH3 to a saturated solution of an ionic compound. Which of the following could the ionic compound be?

1. AgCl or CaF2
2. CaF2
3. Mg(OH)2
4. AgCl
5. SrCO3

3 2

What will happen if 50.0 mL of 0.022 M Na2S2O3, 50.0 mL of 0.010 M AgNO3, and 50.0 mL of 0.097 M KCl are mixed together? For AgCl, Ksp = 1.8 ´ 10^–10; for Ag(S2O ) ^3–, Kf = 2.9 ´ 10¹³.

1. A precipitate of Ag2S2O3 will form.
2. A precipitate of KNO3 will form.
3. No precipitate will form because silver(I) ion exists predominantly as Ag⁺.

3 2

No precipitate will form because silver(I) ion exists predominantly in the complex Ag(S2O ) ^3–.

1. A precipitate of AgCl will form.

Given the two equilibria below,

sp

3 2 3 d

Ag(NH ) ⁺(aq) Ag⁺(aq) + 2NH (aq); K = 5.9 ´ 10^–8 AgCN(s) Ag⁺(aq) + CN^-(aq); K = 2.2 ×10- 16

3 2

what is Kc for the following equilibrium?

AgCN(s) + 2NH3(aq) Ag(NH ) ⁺(aq) + CN^–(aq)

A) 3.7 ×10- 9

B) 1.3 ×10- 23

C) 2.7 ×108

D) 1.4 ×10- 17

E) 5.9 ×10- 8

Given the following equilibrium constants,

3 sp

AgIO K = 3.1 ×10- 8

3 2 f

Ag(NH ) ⁺ K = 1.7 ×107

3 2 3

determine Kc for the dissolution of the sparingly soluble salt AgIO3 in aqueous ammonia (shown below). AgIO3(s) + 2NH3(aq) Ag(NH ) ⁺(aq) + IO ^–(aq)

A) 5.3 ×10- 1

B) 1.8 ×10- 15

C) 5.5 ×1014

D) 1.9

E) 1.7 ×107

What is the molar solubility of nickel(II) sulfide in 0.053 M KCN? For NiS, Ksp = 3.0 ´ 10^–19; for Ni(CN)42–,

Kf = 1.0 ´ 10³¹.

A) 5.5 ´ 10^–10 M

B) 5.3 ´ 10^–2 M

C) 1.5 ´ 10^–19 M

D) 1.3 ´ 10^–2 M

E) 2.2 ´ 10^–5 M

4

What is the molar solubility of zinc hydroxide at pH 12.40? For Zn(OH)2, Ksp = 2.1 ´ 10^–16; for Zn(OH) ^2–,

Kf = 2.8 ´ 10¹⁵.

A) 9.4 ´ 10^–26 M

B) 1.5 ´ 10^–2 M

C) 3.7 ´ 10^–4 M

D) 3.7 ´ 10^–6 M

E) 1.4 ´ 10^–8 M

Which of the following statements concerning the separation of metal ions into Analytical Groups I-V is/are correct?

Only the least soluble sulfides will precipitate in an acidic solution of H2S.
K⁺ and Na⁺ are precipitated in the last step of the separation scheme.
The formation of a precipitate with the addition of dilute HCl(aq) indicates the original solution contains all of the ions of Analytical Group I (the ions which precipitate as chlorides).

1. 1 only
2. 2 only
3. 3 only
4. 1 and 2
5. 1, 2, and 3

Which of the following statements concerning the separation of metal ions into Analytical Groups I-V is/are correct?

The substitution of dilute Zn(Cl)2 for dilute HCl in step one, the precipitation of the Analytical Group I metal ions as chloride salts, will have no effect on the rest of the analysis.
Group I ions cannot be precipitated using this scheme.
In the filtration stages, the filtrate is the solid material that is removed from the mixture by filtration.

1. 1 only
2. 2 only
3. 3 only
4. 1 and 2
5. 1, 2, and 3

In the qualitative analysis scheme for metal ions, how are the Analytical Group III cations separated from the cations of Analytical Groups IV and V?
1. by addition of H2S in acidic solution, forming insoluble metal sulfides
2. by addition of (NH4)2CO3 or (NH4)3PO4, forming insoluble metal carbonates or phosphates
3. by addition of H2SO4, forming insoluble metal sulfates
4. by addition of HCl, forming insoluble metal chlorides
5. by addition of H2S in basic solution, forming insoluble metal sulfides or hydroxides

What is the effect of substituting soluble metal salts such as NaCl and K2CO3 for HCl or (NH4)2CO3 in the qualitative analysis scheme for separating the five Analytical Groups?
1. You can no longer tell if your original sample contained Na⁺ or K⁺.
2. There is no effect on the analysis since Na⁺ and K⁺ do not form a precipitate.
3. The NaCl and K2CO3 are not pure, analytical grade materials.
4. Potassium ion forms a precipitate with sulfide ion.
5. Na⁺ and K⁺ react violently with acids such as H2S, producing highly flammable and potentially explosive hydrogen gas.

In the sulfide scheme for qualitative analysis, the cations of Analytical Group IV are precipitated as phosphates or carbonates. Analytical Group IV consists of
1. alkaline earth elements.
2. the halogens.
3. alkali metals.
4. transition metals having +2 ions.
5. none of these

Consider a solution containing the following cations: Na⁺, Hg²⁺, Mn²⁺, Al³⁺ and Ag⁺. Treatment of the solution with dilute, HCl followed by saturation with H2S, results in formation of precipitate(s). Which ions still remain in solution (did not precipitate)?
1. Na⁺, Hg²⁺, Al³⁺
2. Na⁺ only
3. Ag⁺ and Hg²⁺
4. Ag⁺ only
5. Na⁺, Al³⁺, and Mn²⁺