Chapter 17 - Buffers, Titrations, and Solubility Equilibria

In which of the following would ZnCO3 be least soluble? Choose only ONE best answer. A 0.1M Zn(NO3)2 B 0.1M KNO3 C 0.15M Na2CO3 D 0.1M NaHCO3 E 0.1M CsCl

0.15M Na2CO3 0.1M Zn(NO3)2, 0.15M Na2CO3, and 0.1M NaHCO3 all contain either Zn2+ or CO32- and will decrease the solubility of ZnCO3, but 0.15M Na2CO3 has the highest concentration of one of these species and will result in the lest solubility for ZnCO3.

Which of the following would form a buffer solution? Choose only ONE best answer. A 0.1M HCl and 0.1M NaCl B 0.1M HCl and 0.1M NaOH C 0.1M HCN and 0.1M KCN D 0.1M HF and 0.1M NaOH E 0.1M NaOH and 0.1M KOH

0.1M HCN and 0.1M KCN

Which of the following would form a buffer solution? Choose only ONE best answer. A 0.1M HClO4 and 0.1M RbClO4 B 0.1M HCl and 0.2M NaF C 0.1M HBr and 0.1M KOH D 0.1M HI and 0.1M KNO2 E 1M HNO2 and 1 x 105M NaNO2

0.1M HCl and 0.2M NaF

Which of the following would form a buffer solution? Choose only ONE best answer. A 0.1M HBr and 0.1M KBr B 0.1M HClO4 and 0.1M KOH C 0.1M HClO2 and 0.1M NaClO2 D 0.1M HF and 0.1M NaOH E 0.1M HCl and 0.1MHBr

0.1M HClO2 and 0.1M NaClO2

Which of the following would result in a buffer solution? Choose only ONE best answer. A 0.2M HBr / 0.2M NaOH B 0.2M HCN / 0.2M NaOH C 0.2M HClO / 0.2M NaClO D 0.2M HNO3 / 0.2M KNO3 E 0.2M HF / 0.2M NH3

0.2M HClO / 0.2M NaClO

Which of the following would result in a buffer solution? Choose only ONE best answer. A 0.2M HClO4 / 0.2M NaClO4 B 0.2M HI / 0.1M NaOH C 0.1M HCN / 0.2M KOH D 0.2M NH4Br / 0.2M NH3 E 0.2M HBr / 0.2M KBr

0.2M NH4Br / 0.2M NH3

Which of the following would result in a buffer solution? Choose only ONE best answer. A 0.8M HCl / 0.4M NaCl B 0.2M HBr / 0.1M RbOH C 0.4M HCNO / 0.2M KOH D 0.2M NH4Br / 0.4M LiOH E 0.2M HF / 0.002M KF

0.4M HCNO / 0.2M KOH

Which of the following would result in a buffer with the greatest buffering capacity? Choose only ONE best answer. A 0.4M HNO2 / 0.2M KNO2 B 0.2M HNO2 / 0.4M KNO2 C 0.8M HNO2 / 0.7M KNO2 D 0.8M HNO2 / 0.4M KNO2 E 0.7M HNO2 / 0.1M KNO2

0.8M HNO2 / 0.7M KNO2

What is the maximum concentration of fluoride ions that could be present in 0.032M Ba(NO3)2 (Ksp,BaF2 = 3.2 x 10-8)?

1.0 x 10-3M

What is the molar solubility of a salt of the formula AB3 (Ksp = 3.0 x 10-19)?

1.0 x 10-5M

The molar solubility of FePO4 is 1.1 x 10-11. What is its Ksp value?

1.2 x 10-22

A concentration of Na2CrO4 greater than what must be added to 0.001M AgNO3 for a precipitate to form? (Ksp,Ag2CrO4 = 1.2 x 10-12)

1.2 x 10-6M

What is the molar solubility of Cr(OH)3? (Ksp,Cr(OH)3 = 5.4 x 10-31)

1.2 x 10-8M

The molar solubility of Co(OH)2 is 6.9 x 10-6M. What is its Ksp?

1.3 x 10-15

What is the molar solubility of PbI2? (Ksp,PbI2 = 9.0 x 10-9)

1.3 x 10-3M

What is the molar solubility of Cr(OH)3? (Ksp = 6.7 x 10-31)

1.3 x 10-8M

What is the molar solubility of AgCl (Ksp = 1.8x10-10)?

1.3X10^-5 M

What is the pH after the addition of 20.0mL of 0.10M NaOH to 50.0mL of 0.10M HCl?

1.4

The molar solubility of Fe(OH)3 is 5.0 x 10-10. What is its Ksp value?

1.7 x 10-36

What is the molar solubility of AgCl in 0.1M HCl? (Ksp = 1.8x10-10)

1.8X10^-10

What is the pH after the addition of 55.0mL of 0.10M NaOH to 50.0mL of 0.10M HF (Ka = 6.8 x 10-4)?

11.7

What is the pH after the addition of 10.0mL of 0.15M NaOH to 20.0mL of 0.050M HCl?

12.2

What volume of 0.2M NaOH would be required to completely neutralize 60mL of 0.6M HCl?

180 mL

150mL of 0.10M HCl is titrated with 0.125M NaOH. What is the pH after the addition of the following volumes of NaOH? 100mL

2

The molar solubility of Fe(OH)2 is 8.0 x 10-6. What is Ksp?

2.0 x 10-15

A concentration of NaS greater than what must be added to 0.005M Sn(NO3)2 for a precipitate to form? (Ksp,SnS = 1.0 x 10-26)

2.0 x 10-24M

What is the molar solubility of BaF2 (Ksp = 3.2 x 10-8)?

2.0 x 10-3M

What is the molar solubility of ScF3? (Ksp,ScF3 = 4.2 x 10-18)

2.0 x 10-5M

What is the molar solubility of Cu(OH)2? (Ksp = 4.8 x 10-20)

2.3 x 10-7M

What is the pH after the addition of 10.0mL of 0.10M NaOH to 50.0mL of 0.10M HF (Ka = 6.8 x 10-4)?

2.6

100mL 0.10M HF (Ka = 6.8x10-4 ) is titrated with 0.1M NaOH. Calculate the pH after the addition of the following volumes of 0.1M NaOH. 25mL

2.7

A concentration of NaBr greater than what must be added to 0.02M Cu(NO3)2 for a precipitate to form? (Ksp,CuBr = 5.3 x 10-9)

2.7 x 10-7M

What is the pH of a solution made from 0.2M acetic acid (CH3COOH, pKa = 4.8) and 0.002M sodium acetate (CH3COONa)?

2.8

What volume of 0.1M NaOH is required to completely neutralize 40mL of 0.5M HCl?

200mL

100mL 0.10M HF (Ka = 6.8x10-4 ) is titrated with 0.1M NaOH. Calculate the pH after the addition of the following volumes of 0.1M NaOH. 50mL

3.17 pH=pKa at half-equivalence point

What is the pH after the addition of 25.0mL of 0.10M NaOH to 50.0mL of 0.10M HF (Ka = 6.8 x 10-4)?

3.2

What is the pH of a solution that contains 0.05M HF and 0.05M NaF (Ka,HF = 6.8 x 10-4)?

3.2

The molar solubility of a salt of the formula MX2 is 2.0 x 10-6M. What is the Ksp?

3.2 x 10-17

What is the molar solubility of BaF2 in 0.1M NaF (Ksp,BaF2 = 3.2 x 10-8)?

3.2 x 10-6M

What is the pH of a buffer made from 0.2M acetic acid (CH3COOH, pKa = 4.8) and 0.02M sodium acetate (CH3COONa)?

3.8

What is the molar solubility of CaF2 in 0.01M NaF? (Ksp,CaF2 = 3.9 x 10-11)

3.9 x 10-7M

What volume of 0.2M NaOH is required to completely neutralize 30mL of 0.1M H2SO4?

30mL

What is the pH of a solution that contains 0.003M HF and 0.02M NaF (Ka,HF = 6.8 x 10-4)?

4.0

Sc3+ can be added to a solution of 0.0001M NaF to what maximum concentration before a precipitate forms (Ksp,ScF3 = 4.2 x 10-18)?

4.2 x 10-6M

The Ksp of CaF2 is 3.9 x 10-11. What is the concentration of fluoride ions in a saturated solution of CaF2?

4.3 x 10-4M

What is the pH of a buffer made from 0.4M acetic acid (CH3COOH, pKa = 4.8) and 0.4M sodium acetate (CH3COONa)?

4.8

Which of the following could be the pH at the equivalence point of the titration of NaCN with HClO4?

4.8

Which of the following shows the Ksp expression in terms of the molar solubility, x, for Ni(OH)2 in water? Choose only ONE best answer. A Ksp = x2 B Ksp = 2x3 C Ksp = 4x3 D Ksp = 9x4 E Ksp = 27x4

4x3

Which of the following could be the pH at the equivalence point of the titration of NH3 with HCl? Choose only ONE best answer. A 5.2 B 7.0 C 9.1 D 10.6 E None of these

5.2

What is the pH of a solution that is 0.1M in HA and 0.075M in NaA? (Ka= 2.5X10^-6)

5.5

The molar solubility of AgBrO3 is 7.4 x 10-7M. What is its Ksp?

5.5 x 10-13

What is the pH of a buffer made from 0.04M acetic acid (CH3COOH, pKa = 4.8) and 0.4M sodium acetate (CH3COONa)?

5.8

What volume of 0.4M H3PO4 is required to completely neutralize 30mL of 0.1M Ba(OH)2?

5mL

What does a higher Ksp mean for solubility?

Higher solubility

Which of the following, when properly mixed with its conjugate base, could be used to make a buffer of pH 3.0? I. HF Ka = 6.8 x 10-4 II. H3BO3 Ka = 5.8 x 10-10 III. HCN Ka = 4.9 x 10-10

I only

Which of the following, when properly mixed with its conjugate base, could be used to make a buffer of pH 4.1? I. HClO2 pKa = 2.0 II. HNO2 pKa = 3.3 III. HN3 pKa = 4.7

II and III

pH=

pKa+ log [A-]/[HA]

In which of the following would Ag2S be most soluble? Choose only ONE best answer. A pure water B 0.1M (NH4)2S C 0.2M Na2S D 0.15M AgNO3 E 0.1M K2S

pure water

What are the three ways to prepare a buffer?

Weak Acid / Conjugate Base 1 : 1 Weak Acid / Strong Base 2 : 1 Weak Base / Strong Acid 2 : 1

Which of the following would be more soluble in 0.01M HNO3 than in pure water? Choose only ONE best answer. A ZnBr2 B CsBr C BaCl2 D CaF2 E AlI3

CaF2

What is a buffer composed of?

A weak acid and its conjugate base or a weak base and its conjugate acid

pKa=

-logKa

In which of the following solutions will AgCl be least soluble? Choose only ONE best answer. A 0.1M HCl B 0.15M AgNO3 C 0.08M MgCl2 D 0.01M NaNO3 E Pure water

0.08M MgCl2 0.08M MgCl2 contains 0.16M Cl- and is the correct answer.

What is the pH of a buffer made from 0.004M acetic acid (CH3COOH, pKa = 4.8) and 0.4M sodium acetate (CH3COONa)?

6.8

What volume of 0.25M H3PO4 would be required to completely neutralize 50mL of 0.5M Ba(OH)2?

67mL

What is the pH after the addition of 40.0mL of 0.20M NaOH to 20.0mL of 0.40M HCl?

7.0

Which of the following could be the pH at the equivalence point of the titration of HBr with KOH? Choose only ONE best answer. A 5.2 B 7.0 C 9.4 D 11.9 E 14

7.0

Which of the following could be the pH at the equivalence point of the titration of RbOH with HCl? Choose only ONE best answer. A 1.0 B 5.2 C 7.0 D 9.1 E 10.6

7.0

What is the molar solubility of BaCO3? (Ksp = 5.0 x 10-9)

7.1 x 10-5M

100mL 0.10M HF (Ka = 6.8x10-4 ) is titrated with 0.1M NaOH. Calculate the pH after the addition of the following volumes of 0.1M NaOH. 100mL

7.9

What is the pH after the addition of 50.0mL of 0.10M NaOH to 50.0mL of 0.10M HF (Ka = 6.8 x 10-4)?

7.9

The molar solubility of BiI3 is 1.32x10-5 . Calculate Ksp.

8.19X10^-19

What is the molar solubility of AgI in 0.01M KI? (Ksp,AgI = 8.3 x 10-17)

8.3 x 10-15M

Which of the following could be the pH at the equivalence point of the titration of HC2H3O2 with CsOH? Choose only ONE best answer. A 2.0 B 5.1 C 7.0 D 8.4 E 12.1

8.4

What is the molar solubility of BaSO3 (Ksp = 8.0 x 10-7)?

8.9 x 10-4M

What volume of 0.1M KOH would be required to completely neutralize 100mL of 0.4M H2SO4?

800mL

What volume of 0.15M H2SO3 is required to completely neutralize 24mL of 0.1M KOH?

8mL

Which of the following could be the pH at the equivalence point of the titration of HOCl with NaOH? Choose only ONE best answer. A 1.2 B 4.8 C 7.0 D 9.1 E 13.5

9.1

What is the pH after the addition of 20.0mL of 0.20M HBr to 100.0mL of 0.10M NH3 (Kb = 1.8 x 10-5)?

9.4

NaI is added to a final concentration of 1.0 x 10-5M to a solution of 0.0002M Bi(NO3)3. Which of the following is true? (Ksp,BiI3 = 8.2 x 10-19) Choose only ONE best answer. A A precipitate forms because Qsp < Ksp B A precipitate forms because Qsp > Ksp C A precipitate will not form because Qsp < Ksp D A precipitate will not form because Qsp > Ksp E None of these

A precipitate will not form because Qsp < Ksp

500ml of 2 x 10-5M AgNO3 is added to 500ml of 1 x 10-5M NaCl. Which of the following accurately describes the solution? (Ksp,AgCl = 1.8 x 10-10) A A precipitate forms because Qsp < Ksp B A precipitate forms because Qsp > Ksp C A precipitate will not form because Qsp < Ksp D A precipitate will not form because Qsp > Ksp E None of these

A precipitate will not form because Qsp < Ksp This question is tricky. Mixing 500ml of 2 x 10-5M AgNO3 with 500ml of 1 x 10-5M NaCl dilutes both concentrations in half (You can use M1V1 = M2V2 to figure this out). These final concentrations after mixing are therefore 1 x 10-5M AgNO3 and 0.5 x 10-5M NaCl (or 5.0 x 10-6M NaCl). The solubility reaction and the corresponding Ksp expression are as follows: AgCl(s) ⇌ Ag+(aq) + Cl-(aq) Ksp = [Ag+][Cl-] (at equilibrium) Qsp = [Ag+][Cl-] (not necessarily at equilibrium) Qsp = (1 x 10-5)(5 x 10-6) Qsp = 5 x 10-11 which is less than 1.8 x 10-10

Buffer

A solution that resists changes in pH.

Basic salts are more soluble in _____ solutions, less soluble in ______.

Acidic; basic

Rank the following in order of decreasing solubility. Ksp AgBr 5.0 x 10-13 PbCO3 7.4 x 10-14 MnS 2.0 x 10-53

AgBr > PbCO3 > MnS

Which of the following would be more soluble in basic conditions than in pure water? Choose only ONE best answer. A RbCl B BaCl2 C SrS D Al(NO3)3 E NaNO2

Al(NO3)3 Acidic salts more soluble in basic solutions

Which of the following could be used, when mixed in the right proportions, to prepare a buffer solution? Choose only ONE best answer. A weak acid with conjugate base B weak base with conjugate acid C weak acid with strong base D weak base with strong acid E All of the above

All of the above

Which of the following is false about the titration of HF with NaOH? Choose only ONE best answer. A At the equivalence point moles HF = moles F-. B The pH is greater than 7 at the equivalence point. C At the half-equivalence point pH = pKa. D At the half-equivalence point [F-] = [HF]. E HF and NaOH react in a 1:1 ratio.

At the equivalence point moles HF = moles F-. In a titration of HF with NaOH which react in a 1:1 ratio, it is the moles of NaOH added that equals the moles of HF (not moles HF = moles F-; this is the false statement.

Acidic salts are more soluble in____ solutions, less soluble in _____.

Basic; acidic

Which of the following would have a solubility that is largely independent of a change in pH? Choose only ONE best answer. A KF B NH4Br C FeCl3 D NaOCl E CsClO4

CsClO4

Which of the following shows the Ksp expression in terms of the molar solubility, x, for LaF3 in water? Choose only ONE best answer. A Ksp = x2 B Ksp = 2x3 C Ksp = 4x3 D Ksp = 9x4 E Ksp = 27x4

Ksp = 27x4

What is the Ksp expression for Cr(OH)3?

Ksp = [Cr3+][OH-]3

What is the Ksp expression for MgO?

Ksp = [Mg2+][O2-]

What is the Ksp expression for SrF2?

Ksp = [Sr2+][F-]2

Which of the following shows the Ksp expression in terms of the molar solubility, x, for AgI in water? Choose only ONE best answer. A Ksp = x2 B Ksp = 2x3 C Ksp = 4x3 D Ksp = 9x4 E Ksp = 27x4

Ksp = x2

Which of the following would be more soluble in basic conditions than in pure water? Choose only ONE best answer. A KClO4 B NaHSO4 C CaCO3 D Mg(OH)2 E LiCN

NaHSO4

Is the solubility of neutral salts affected by a change in pH?

No

When 0.1 moles of HCl is added to 1L of a solution containing 0.5M HCN and 0.5M NaCN, which of the following is true? Choose only ONE best answer. A The pH = 1 B The pH will increase a little. C The pH will increase a lot. D The pH will decrease a little. E The pH won't change at all.

The pH will decrease a little.

To a 0.0001M solution of Mg(NO3)2, NaOH was added to a final concentration of 0.001M. Did a precipitate form? (Ksp Mg(OH)2 = 1.6x10-12)

Yes Qsp=1X10^-10

What is the molar solubility of Mg(OH)2 (Ksp = 1.6x10-12)?

[Mg]=7.4X10 [OH-]= 5.5X10^-9