1. Answers may vary. Sample answer: We eat citrus fruits and tomatoes, which contain acids. Processed foods such as pop and sour candy also contain acids.
2. b
3. The process of demineralization causes teeth to soften.
4. Answers may vary. Sample answer: Two characteristic properties of acids are that their pH is less than 7 and they react with metals above hydrogen on the activity series to produce hydrogen gas.
5. Answers may vary. Sample answer: Two characteristic properties of bases are that their pH is greater than 7 and they react with carbon dioxide to form carbonates.
6. When acids and metals react, hydrogen gas and compounds of the metal are produced.
7. False. When a base reacts with carbon dioxide, carbonates are formed.
8. In a chemical equation, if the chemical formula of a compound starts with one or more hydrogen atoms, it is usually an acid.
9.
Table 1 Acid and Base Properties
Property pH of 9
Acid or base base sour taste no special feel acid acid
10.
(a) chlorous acid
(b) The oxyanion is ClO
2
–
, chlorite ion.
11. Hydroxide bases only show their basic properties when they are in solution.
1. Figure 1
2. During the process of dissociation , individual ions separate from an ionic compound as it dissolves in water.
3. The chemical formula that can be used to simplify an acid base neutralization reaction is:
H
+
(aq) + OH
–
(aq) → H
2
O(l)
Copyright © 2011 Nelson Education Ltd. Chapter 10: Acids and Bases 10-1

4.
Ionization involves the formation of ions from uncharged molecules.
5. Ionization of nitric acid:
Total ionic equation: H
+
Net ionic equation: H
+
HNO
(aq) + OH
–
3
(aq)
(aq) + NO
3
Balanced chemical equation: HNO
3
–
→ H
(aq) → H
2
+
(aq) + K
(aq) + NO
Dissociation of potassium hydroxide: KOH(s) → K
O(l)
+
3
–
(aq) + OH
+
(aq) + OH
(aq) + KOH(s) → H
(aq)
–
(aq)
–
(aq) → H
2
O(l) + NO
2
O(l) + KNO
3
(aq)
6. False. A weak acid is a substance that only partially ionizes in water.
3
–
(aq) + K
+
(aq)
7. Some acids, called weak acids, do not ionize as well when compared to other acids in the same concentration. The lower ionization also causes them not to conduct electricity as well as those acids that ionize more completely.
8. A change of one pH unit represents a tenfold change in how acidic or basic a solution is.
1. True
2. Generally, when performing an acid–base titration in the lab, you look for a sudden and obvious change, such as the colour of an acid-base indicator, in the solution you are working with to determine when you have reached the equivalence point.
3. False. Acid-base indicators do not change colour at a specific value.
4.
Answers may vary. Sample answer: During a titration, you want to ensure that you make accurate and precise observations. Make sure to accurately determine the volume of titrant required to reach the equivalence point.
5.
The endpoint is the point during a titration when a sudden change in an observable property of the solution occurs; usually a change in colour of an acid-base indicator or a significant change in pH.
6. Generally, when performing an acid–base titration in the lab, you look for a sudden and obvious change, such as the colour of an acid-base indicator, in the solution you are working with to determine when you have reached the equivalence point.
7. (a) The solution is a base.
(b) You could use methyl red, thymol blue, or phenolphthalein to determine whether a substance is a base.
8 . A titration gives accurate results only when its endpoint coincides with its equivalence point .
9. 275 mL – 250 mL = 25 mL
A volume of 25 mL of titrant was used in the experiment.
10. A chemical that is highly pure and chemically stable is a primary standard .
11. Given: mass of base, m
3
= 0.425 g ; volume of acid, V
HCl
= 0.255 L
Required: amount concentration of hydrochloric acid, c
HCl
Analysis: c = n
V
Solution:
Step 1: Write a balanced equation for the reaction.
K
2
CO
3
(aq) + 2 HCl(aq) → 2 KCl(aq) + CO
2
(aq) + H
2
O(l)
Step 2: Convert the mass of K
2
CO
3
to amount of K
2
CO
3
. n
3
= 0.425 g "
1 mol
138.21 g
3 n
3
= !
3
Step 3: Use the amount of K
2
CO
3
and the mole ratio in the balanced equation to determine the amount of HCl. n
HCl
= !
3
3
"
2 mol
HCl
1 mol
3 n
HCl
=
Copyright © 2011 Nelson Education Ltd. Chapter 10: Acids and Bases 10-2

Step 4: Use the concentration equation to determine the amount concentration of HCl. c
HCl
= n
HCl
V
HCl c
HCl
!
3
=
=
0.255 L
0.0241 mol/L
Statement: The amount concentration of the hydrochloric acid solution is 0.0241 mol/L.
1. An acid that completely ionizes in water is a strong acid.
2. False. Hydroxide ions give bases their characteristics.
3. You can determine if a compound is an acid by noting if the chemical formula of the compound starts with one or more hydrogen atoms.
4. Table 1 Acids That Do Not Contain Oxygen
Acid name hydrochloric acid hydrosulfuric acid hydrofluoric acid
Chemical formula (aq)
HCl
H
2
S
HF
5. Chemists use two different systems to name acids depending on whether the compound contains oxygen.
6. According to the Arrhenius theory, when electrolytes dissolve, its ions dissociate .
7. Ionization of phosphoric acid: H
3
PO
4
(aq) → 3 H
Dissociation of sodium hydroxide: NaOH(s) → Na
+
+
(aq) + PO
(aq) + OH
4
–
3–
(aq)
(aq)
Balanced chemical equation: H
Total ionic equation: 3 H
Net ionic equation: 3 H
+
+
3
PO
(aq) + PO
4
(aq) + 3 OH
(aq) + 3 NaOH(s) → Na
3
PO
4
4
–
3–
(aq) + 3 Na
+
(aq) → 3 H
2
(aq) + 3 OH
–
(aq) + 3 H
2
O(l)
(aq)
O(l), or simply: H
+
→ 3 H
2
O(l) + 3 Na
(aq) + OH
–
+
(aq) + PO
4
3–
(aq)
(aq) → H
2
O(l)
8.
In order for a titration to give accurate results, the endpoint must coincide with the equivalent point, meaning that the acid-base indicator that is used must change colour when the equivalence point is reached.
9.
Titrations require standard solutions.
10.
To ensure that the endpoint has been reached, when the addition of a drop of titrant produces a permanent colour change, record the burette volume. Then add another drop of titrant to see if there is a change. If there is no change, you are likely at the endpoint and have just passed it.
11. Given: mass of acid, m
3 2
= 0.450 g ; volume of base, V
NaOH
= 0.500 L
Required: amount concentration of sodium hydroxide solution, c
NaOH
Analysis: c = n
V
Solution:
Step 1: Write a balanced equation for the reaction.
HC
2
H
3
O
2
(aq) + NaOH(aq) → NaC
2
H
3
O
2
(aq) + H
2
O(l)
Step 2: Convert the mass of HC
2
H
3
O
2
to amount of HC
2
H
3
O
2
. n
3 2
= 0.450 g "
1 mol
60.06 g
3 2 n = !
3
3 2
Step 3: Use the amount of HC
NaOH.
2
H
3
O
2
and the mole ratio in the balanced equation to determine the amount of n
NaOH
= !
3
3 2
"
1 mol
1 mol
NaOH
3 2 n
NaOH
= 7.4925 10
!
3 " 10 mol (two extra digits carried)
Copyright © 2011 Nelson Education Ltd. Chapter 10: Acids and Bases 10-3

Step 4: Use the concentration equation to determine the amount concentration of NaOH. c
NaOH
= n
NaOH
V
NaOH c
NaOH
=
=
0.500 L
0.0150 mol/L
Statement: The amount concentration of the sodium hydroxide solution is 0.0150 mol/L.
1. a
2. a
3.
False. The water cycle describes the movement of water on, above, and below Earth’s surface.
4. Hydrocarbons are held together by weak London forces, which are non-polar. So, there are almost no attractive forces between hydrocarbon molecules and water molecules. As a result, they do not mix.
5. A chemical equation for the dissociation of potassium chloride, KCl, is: KCl(s) → K
+
(aq) + Cl
–
(aq)
6. Figure 1
Any point above the solubility curve would be considered a supersaturated solution, and any point below the curve would be considered an unsaturated solution.
7. Given: m
AgNO
3
= 0.45 g ; V
AgNO
3
= 0.500 L
Required: amount concentration of silver nitrate solution, c
AgNO
3
Analysis: c = n
V
Solution:
Step 1: Convert mass of silver nitrate to amount of silver nitrate. n
AgNO
3
= 45 g !
1 mol
AgNO
3
169.88 g n
AgNO
3
= 0.2649 mol (two extr digits carried)
Step 2: Substitute the values in the amount concentration equation. c
AgNO
3
= n
AgNO
3
V
AgNO
3 c
AgNO
3
=
=
0.2649 mol
0.500 L
0.53 mol/L
Statement: The amount concentration of the silver nitrate solution is 0.53 mol/L.
8. When doing a dilution, you can decrease the concentration by adding more solvent.
9. Silver is below copper in the activity series so it will not displace copper from copper (II) chloride. So, the formula equation for the reaction that occurs between silver and copper(II) chloride, CuCl
Ag(s) + CuCl
2
(aq) → no reaction
2
, is:
Copyright © 2011 Nelson Education Ltd. Chapter 10: Acids and Bases 10-4

10.
Qualitative analysis involves the identification of a substance. Quantitative analysis involves determining how much of a substance is present.
11.
The chemical name for H
3
PO
4
(aq) is phosphoric acid.
12. Table 1 Anions and Formulas
Anion perchlorate chlorate chlorite
Formula of anion
ClO
ClO
ClO
4
–
3
–
2
–
13.
The Arrhenius theory of acids and bases states that acids ionize in water to produce hydrogen ions, and bases dissociate in water to produce hydroxide ions.
14.
A primary standard should react completely and have a large molecular mass when used in a titration.
Copyright © 2011 Nelson Education Ltd. Chapter 10: Acids and Bases 10-5