CHEM 12

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ACID AND BASE UNIT REVIEW

CONCEPTS

1. List the properties of acids and bases.

2. What ion is produced when an acid reacts with water? A base?

3. Define: conjugate, Arhenius acid and base, Bronsted acid and base, weak acid, strong acid, ionization, equivalence point of a titration, transition point of an indicator (write an equation), buffer and hydrolysis.

4. Identify the acids or bases in the following equation. Are the reactants or products favoured?

HC0₃^- + HF<-----> H₂CO₃ + F^-

5. Classify each compound as a strong or weak acid or base; acidic or basic anhydride; acidic, basic, or neutral salt; or buffer system. Write an equation to show how each reacts with water.

NH3	AlCl3	H2CO3	HClO4	KCN	NH4Cl	KOH
SO2	NaF	HCl	NaI	K2O	NaOH	CO2

NH3 and NH4Cl

NaCH3COO and CH3COOH

6. H⁺is short for _______.

7. Determine the conjugates for each of the bases.

CN^-

NH3

F^-

OH^-

Co(H2O)5(OH)^+2

8. Determine the conjugates for each of the acids.

HF

HCN

Al(H2O)6^+3

NH4^+

HPO4^-2

9. Describe a strong and weak acid as well as a strong and weak base in terms of each of the following:

Conductivity, Size of Ka or Kb, Degree of Ionization and pH.

10. Why is the strongest acid in water H₃O⁺? Explain!

11. Why is the strongest base in water OH^-? Explain!

12. Which has the higher pH H₂S0₃ or H₃BO₃? Explain!

13. Which has the higher pH NaCN or NaF? Explain!

14. A buffer has a pH of 9.00. 2 drops of a dilute strong acid are added. Estimate how the pH changes?

15. a) Complete the chart by indicating the pairs required to make buffer solutions. For example HCN (weak acid) and NaCN (salt containing the conjugate of the weak acid) will make a buffer solution. b) Write an equation the describes the equilibrium for each buffer. c) Circle the formulas that have high concentrations.

Weak Acid or Base	Salt
HF
	NaCH3COO
NH3
	NaCN
H2CO3
	K3PO4
HCH3COO

16. Match each equation with its type:

Acid/base formula equation	F^- + HOH(l) <-----> HF + OH^-
Acid/base net ionic equation	HCl + NaOH ----->NaCl + HOH(l)
Solubility product ionization equation	H^+ + OH^- -----> HOH(l)
Hydrolysis of a weak acid	AgCl(s)< -----> Ag^+ + Cl^-
Hydrolysis of a weak base	H20(l) <-----> H^++ OH^-
Ionization of water	NH4^+ + H20 <-------> NH3 + H3O^+

17. Write the equilibrium expressions for each of the above equations except for the second and third reactions.

18. A student tested the electrical conductivity of two acid solutions. One solution was a strong acid and the other a weak acid. Both solutions had the same conductivity. Explain how this could be possible.

19. Describe in terms of hydrolysis how NaCH₃COO can be added to potato chips in order to produce the vinegar flavour.

20. Describe what happens to the H⁺ and the OH^- when the pH increases by 2 units.

21. Describe two gases responsible for acid rain. Write equations to show how they react with water. What gas naturally lowers the pH of normal rain?

22. Complete the following reaction using a formula equation, complete ionic equation and net ionic equation. H₂C₂O₄ + NaOH ----->

23. Write the equilibrium expression for phosphoric acid in water.

24.

a) An indicator HInd is red in acid and blue in base. Write the equation for the indicator and explain the colours.

b) What is true at the transition point?

c)What is the color of this indicator in a solution of AlCl₃?

d) In the above solution, what is larger [HInd] or [Ind^-] ?

e) Calculate the Ka for Phenolphthalein.

f) What indicator has a Ka of approximately 1.0 X 10^-10?

25. Give an example of a monoprotic, diprotic, and triprotic acid. Write an equation for each to show how they ionize in water.

26. Give the approximate pH of the equivalence for each titration. Choose an appropriate indicator.

Acid	Base	pH of Equvalence Point	Indicator
HCl	NaOH
H2SO4	NH3
HF	KOH

27. Which of the following will have the lowest pH?

HCLO

HClO2

HClO3

HClO4

28. Pick a formula that is amphriprotic.

H2SO4	H20	F^-	HCO3^-
CO3^-2	KOH	H2PO4^-	HPO4^-2

CALCULATIONS

1. Calculate the quantities required to complete the table. In the first row write the general equations for each quantity. Watch your significant figures.

[H^+] =	[OH^-] =	pH =	pOH =
[H^+]	[OH^-]	pH	pOH	Acid/base/neutral
5.0 x 10^-3M
	1.3 x 10^-5M
		3.1
			2.508
				neutral (2sig figs)

2. What volume of .20M H₂SO₄ is needed to neutralize 50.00 ml .30M NaOH?

3. What mass of NaF is required to prepare 100ml of .300M solution?

4. 35.5 ml of .300M NaOH is required to neutralize 10.0 ml of H₂SO₄. What is the acid concentration?

5. 100 ml of .200 M HCl is mixed with 120ml of .200M NaOH. Calculate the pH of the resulting solution.

6. Calculate the Ka for phenolphthalein.

7. The Ksp of AgOH is 6.8x10^-12. Calculate the pH.

8. The OH^- concentration in .10M NaCN is 2.7x10^-6M. Calculate the Kb from this information only.

9. Calculate the pH for .20M HCl.

10. Calculate the pH for .10M Ba(OH)₂.

11. Calculate the pH for .40M HCN.

12. Calculate the pH for .40M Na₂CO₃.

13. What is the pH for .30M NaCl?

14. Calculate the pH of .20M NH₃.

15. Calculate the pH of .20M NH₄Cl.

16. Show by calculation if H₂PO₄^- is an acid or base (compare the Kb and Ka).

17. Calculate the pH of a saturated solution of Mg(OH)₂ if the Ksp is 1.2 X 10^-11.

18. A .50M NH₃ solution is found to have a OH^- concentration of 1.86 x 10^-3 M. Using this data only calculate the Kb.

19. A .18M acid HX has a pH of 2.40. What is the Ka?

20. The following data were recorded when 25.00ml of H₂SO₄ were titrated with .1030M NaOH. The volumes of NaOH used in three runs were: 46.06ml, 44.52ml, 44.54ml. Calculate the acid concentration.

21. The following data were recorded when 10.00ml of NaOH were titrated with .1030M H₂SO₄. The volumes of H₂SO₄ used in three runs were: 12.55ml, 12.55ml, 12.10ml. Calculate the base concentration.

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