1. NaHCO₃ + KHSO₄

HCO₃^- + HSO₄^- ⇋ H₂CO₃ + SO₄^2-

Base Acid Acid Base

2. 0.0186 g x 1mole

[Ag₂CO₃] = 275.8 g = 0.0001349 M

.500 L

Ag₂CO_3(s) ⇋ 2Ag⁺ + CO₃^2-

0.000270 M 0.0001349 M

Ksp = [Ag⁺]²[CO₃^2-]

= (0.000270)²(0.0001349)

= 9.82 x 10^-12

Anything that will react with Ag⁺ or CO₃^2- will work.

NaCl Cl^- has low solubility with Ag⁺

Ba(NO₃)₂ Ba²⁺ has low solubility with CO₃^2-

HCl Reacts with CO₃^2- which is a base

Many other answers are possible.

3. NH₄Br and KHCO₃

a) NH₄Br + KHCO₃ ⇋ NH₃ + H₂CO₃

b) NH₄⁺ + HCO₃^- ⇋ NH₃ + H₂CO₃

c) Reactants are favoured as H₂CO₃ is a stronger acid than NH₄⁺.

4. 2HCl + Mg(OH)₂ → MgCl₂ + 2HOH

pH = 0.90 [H+] = 10^-0.90 = 0.1259 mole x .065 L = 0.008183 moles

1 L

pH = 1.50 [H+] = 10^-1.50 = 0.03162 mole x .065 L = 0.002055 moles

1 L

The difference here is the moles HCl that needs to be neutralized = 0.006128 moles

0.006128 moles HCl x 1 mole Mg(OH)₂ x 58.3 g = 0.18 g

2 mole HCl

5. HOCl + C₃H₅O₃^- ⇋ HC₃H₅O₃ + OCl^-

Acid Base Acid Base

As the stronger base OCl^- is on the right, the other side or the reactants are favoured in this equilibrium. This is because the base on the right is more successful at accepting protons, which makes reactants.

6. Rate One = 12 mL = 3 mL/min Rate One = 6 mL = 1 mL/min

4 min 6 min

HCL CH₃COOH

Rate One is the strong acid HCl, which would have a higher [H⁺] and hence a greater rate.

7. Mg(OH)₂ is a weak base and partially ionizes in water.

MgF₂ is a basic salt which the F^- ion partially accepts a proton from water.

8. pH 3.0 6.0 12.0

methyl red red yellow yellow

Thymolphthalein colourless colourless blue

Combined Colour red yellow green

9. NaHCO₃ and Na₂CO₃ are both basic salts. CO₃^2- is a stronger base than HCO₃^- and will have a higher pH.

Colour pH Base

Alizarin Yellow yellow 10 or less HCO₃^-

Orange 11.0 CO₃^2-

10. This sounds like something Mitch and Andre might do, however…………………..

pH = 4.60 [H⁺] = 10^-4.60 = 0.000025119 moles x 135 L = 0.003391 moles HCl

1 L

CaO is an basic anhydride and reacts with water as such: CaO + H₂O → Ca(OH)₂

The Ca(OH)₂ will neutralize the HCl. Ca(OH)₂ + 2HCl → CaCl₂ + H₂O

0.003391 moles HCl x 1 mole Ca(OH)₂ x 1 mole CaO x 56.1 g = 0.095 g CaO

2 mole HCl 1 mole Ca(OH)₂ 1 mole

11. NaNO₂ is a high solubility salt and is a good conductor.

CH₃COOH is a weak acid and has moderate conductivity.

12. a) HCOOH + NH₃ ⇋ NH₄⁺ + HCOO^-

b) The products are favoured as HCOOH is a stronger acid than NH₄⁺.

c) NaHCO₃ is a basic salt and the basic ion is HCO₃^-.

13. K₂O + H₂O → 2KOH → 2K⁺ + 2OH^-

0.40 M 0.80 M 0.80 M

pOH = 0.10 pH = 13.90

14. (NH₄)₂C₂O₄ This salt has an acid part NH₄⁺ and a base part. Neither one can be crossed out as a neutral ion.

NH₄⁺ + H₂O ⇋ H₃O⁺ + NH₃

C₂O₄^2- + H₂O ⇋ HC₂O₄^2- + OH^-

15.

CH₃COOH + NaOH → NaCH₃COO + H₂O

The Basic salt makes the equivalence point higher than 7.

16. pH = 2.30 [H+] = 10^-2.30 = 0.005012 M

C₆H₅COOH ⇋ H⁺ + C₆H₅COO^-

I x 0 0

C 0.005012 M 0.005012 M 0.005012 M

E x - 0.005012 M 0.005012 M 0.005012 M

Ka = (0.005012)² = 6.5 x 10^-5

(x - 0.005012)

0.00002512 = .000065x - .0000003278

0.00002545 = .000065x

x = 0.3915 M

0.200 L x 0.3915 moles = 0.078 moles

L

17. MgCO_3(s) ⇋ Mg²⁺ + CO₃^2-

Adding Ca(NO₃)₂ increases Ca²⁺ which reacts with CO₃^2- lowering it. This cause the reaction to shift to the right and more MgCO₃ dissolves.

18. H₂PO₄^- + HCO₃^- ⇋ HPO₄^2- + H₂CO₃

Acid Base Base Acid

19. Property Strong Acid Weak Acid

Ka Value very large small

Degree of ionization complete partial

[H⁺] large small

Strength of Conjugate Base weaker stronger

20. C₁₂H₂₁O₃N + H₂O ⇋ C₁₂H₂₁O₃NH⁺ + OH^-

I 0.020 M 0 0

C x x x

E 0.020 – x x x

Small Kb approximation 0.020 – x = 0.020

x² = 1.6 x 10^-6

0.020

x = [OH^-] = 0.00017888

pOH = 3.75

pH = 10.25

21. a) H₂TeO₄ Large Keq means the products are favoured and acid on left is favoured.

b) H₂SeO₃ Large Keq means the products are favoured and acid on left is favoured.

c) H₂SeO₃

H₂TeO₄

HTeO₄^-

HSeO₃^-

22. Zn(OH)_2(s) ⇋ Zn²⁺ + 2OH^-

Adding HCl increases the [H⁺] which reacts with the OH^-, lowering the [OH^-] and the equilibrium shifts right causing more Zn(OH)_2(s) to dissolve.

23. This is a titration and a weak base calculation.

Titration

HCl + B^- → HB + Cl^-

0.032 L 0.02000 L

0.500 M ? M This comes from the titration curve equivalence point.

[B^-] = 0.032 L HCl x 0.500 mole x 1 mole B^-

1 L 1mole HCl

0.02000 L

= 0.80 M

Weak Base pH = 11.00 pOH = 3.00 [OH^-] = 0.0010 M

B- + H₂O ⇋ HB + OH^-

I 0.80 M 0 0

C - 0.0010 + 0.0010 + 0.0010

E 0.799 0.0010 0.0010

Kb = (0.0010)² = 1.3 x 10^-6

0.799

24. H₂PO₄^2- + S^2- ⇌ HPO₄^2- + HS^-

The products are favoured because H₂PO₄^2- is a stronger acid than HS^-.

This means that the HS^- is in higher concentration.

25. 3 6 10

Thymol Blue yellow yellow blue

Methyl Red red yellow yellow

Thymolpthalein clear clear blue

Color orange yellow green

26. H₃O⁺ is the only acid to exist in water as all strong acids completely turn into H₃O⁺.

HCl + H₂O → H₃O⁺ + Cl^-

27. HOCl ⇌ H⁺ + OCl^-

HOBr ⇌ H⁺ + OBr^-

HOI ⇌ H⁺ + OI^- Strongest Base, NaOI will be the most basic.

28. Acid rain dissolves metal, limestone, and concrete structures in our cities. This is very expensive.

Acid rain leaches toxic metals from the rocks in rivers and streams and carries them into the

lakes where they concentrate. This is harmful to marine life.

29. pH = 10.98 pOH = 3.02 [OH-] = 0.000955 M

NH₃ + H₂O ⇌ NH₄⁺ + OH^-

I 0.0045 M 0 0

C 0.000955 0.000955 0.000955

E 0.003545 0.000955 0.000955

Kb = [0.000955][0.000955] = 2.5 x 10^-4

0.003545

30. HS^- + HSO₃^- ⇌ H₂S + SO₃^2-

Acid Acid

Slightly stronger, so the products a favoured slightly Keq > 1

31. CaCO₃ is a basic salt which neutralizes the acid rain.

32. Thymol blue is a diprotic indicator which changes color twice as it loses two protons.

H₂Ind ⇌ H⁺ + HInd^-

red yellow [H₂Ind] = [HInd^-] orange

HInd^- ⇌ H⁺ + Ind^2-