10. Shown below is a chart of acids, their conjugate bases, and their Ka and Kb values. Fill in
the missing information. (Ka x Kb = Kw = 1 x 10-14)
Ka
Acid
Base
Kb
Strong acid
HNO3, HI, HCl, etc.
NO3-1, I-1, Cl-1, etc.
Negligible basicity
1.3 x 10-2
HSO4-1
SO4-2
7.7 x 10-13
7.1 x 10-4
HNO2
NO2-1
1.4 x 10-11
6.8 x 10-4
HF
F-1
1.5 x 10-11
1.8 x 10-5
CH3COOH
CH3COO-1
5.6 x 10-10
4.5 x 10-7
H2CO3
HCO3-1
2.4 x 10-8
9 x 10-8
H2S
HS-1
1 x 10-7
5.6 x 10-10
NH4+1
NH3
1.8 x 10-5
6.2 x 10-10
HCN
CN-1
1.6 x 10-5
4.7 x 10-11
HCO3-1
CO3-2
2.1 x 10-4
1 x 10-17
HS-1
S-2
1 x 103
Negligible acidity
Li+1, Na+1, Ca+2, etc.
O-2, OH-1
Strong base
Salts are ionic compounds, which dissociate in water to produce ions. They are formed in a
neutralization reaction between acids and bases. Depending on the nature of the acids and
bases (strong or weak), the solutions of the salts will be acidic, basic, or neutral.
11. Determine which of the following salts will form acidic, basic or neutral solutions when
dissolved in water. (Hint: look at the acids and bases that formed them)
For example: KCH3COO was formed in the reaction between KOH and CH3COOH
KOH is a strong base. Its conjugate acid, K+1, has negligible acidity and will leave the pH
at 7.00, a neutral solution.
CH3COOH is a weak acid, making its conjugate base, CH3COO-1 a relatively strong base.
It will produce a basic solution.
Analyze the following salts in the same way.
a. KF
– basic salt
WCA SCB
– neutral salt
WCA WCB
(KOH – SB, HCN – WA)
e. RbI
– neutral salt
WCA WCB
(NaOH – SB, HNO3 – SA)
c. NH4NO3
– basic salt
WCA SCB
(KOH – SB, HF – WA)
b. NaNO3
d. KCN
– acidic salt
SCA WCB
(NH3 – WB, HNO3 – SA)
(RbOH – SB, HI – SA)
f. Na2CO3
– basic salt
WCA SCB
(NaOH – SB, H2CO3 – WA)
True and False
12.
13.
14.
15.
16.
17.
18.
The larger the value of Ka, the stronger the acid. (True)
The stronger an acid, the stronger its conjugate base. (False)
The strongest acid that can exist in aqueous solutions is perchloric acid. (False)
The strongest base that can exist in aqueous solutions is the OH-1 ion. (True)
A solution with a pH of 13 would be acidic. (False)
A solution with a pOH of 12 would be basic. (False)
The hydrogen ion concentration in a solution with a pH of 5.65 is ten times that of one with
a pH of 6.65. (True)
Choose the correct word
19.
20.
21.
22.
The greater the degree of dissociation, the (stronger, weaker) the acid.
Acids, bases, and salts are (electrolytes, nonelectrolytes).
CH3COOH is a(n) (acid, base, salt).
NH4Cl is a(n) (acid, base, salt).
23.
24.
25.
26.
27.
The stronger the acid, the (weaker, stronger) the conjugate base.
pH values (can, cannot) go off the 0-14 pH scale.
Buffers maintain a(n) (definite, indefinite) pH.
A pH of 2 is (100, 10, 2) times (more, less) acidic than a pH of 4.
Because a bicarbonate ion, HCO3-1, can both donate and accept a proton under certain
conditions it is said to be a(n) (Arrhenius, amphiprotic) species.
28. Determine the pH and pOH of each of the following solutions and indicate whether each is
acidic, basic, or neutral.
a. Milk, [H3O+1] = 3.2 x 10-7 M (pH = 6.49, pOH = 7.51, Acidic)
b. Pickle Juice, [H3O+1] = 2.0 x 10-4 M (pH = 3.70, pOH = 10.30, Acidic)
c. Beer, [H3O+1] = 3.2 x 10-5 M (pH = 4.49, pOH = 9.51, Acidic)
d. Blood, [H3O+1] = 4.0 x 10-8 M (pH = 7.40, pOH = 6.60, essentially neutral)
29. Determine the [H3O+1] and [OH-1] of each of the following solutions, and indicate whether
each is acidic, basic, or neutral.
a. Lime Juice, pH = 1.9 ([H3O+1] = 1. x 10-2, [OH-1] = 8 x 10-13, Acidic)
b. Tomato juice, pH = 4.2 ([H3O+1] = 6 x 10-5, [OH-1] = 2 x 10-10, Acidic)
c. Saliva, pH = 7.0 ([H3O+1] = 1 x 10-7, [OH-1] = 1 x 10-7 , Neutral)
d. Kitchen cleanser, pH = 9.3 ([H3O+1] = 5 x 10-10, [OH-1] = 2 x 10-5, Basic)
30.
Predict the characteristic of the solutions of the following salts.
a. CrBr3 (acidic)
c. NaCl (neutral)
b. NH4ClO4 (acidic)
d. K2CO3 (basic)
31. The Ka values for HPO4-2 and HSO3-1 are 4.8 x 10-13 and 6.3 x 10-8 respectively. Therefore
it follows the HPO4-2 is a weaker acid than HSO3-1 and PO4-3 is a stronger base than SO3-2.
32. Given the following Ka values, determine which species is the strongest base.
HSO4-1
1.2 x 10-2
-1
H2PO4
6.3 x 10-8
HCO3-1
4.7 x 10-11
33. Given the following Ka values, determine which species is the strongest base.
HF
6.8 x 10-4
HNO2
4.5 x 10-4
HCNO
2.2 x 10-4
34. Consider the following salts. Which one(s) when dissolved in water will produce a neutral
solution?
1) CaCl2
2) Sr(NO3)2
3) K2CO3
35. Consider the following salts. Which one(s) when dissolved in water will produce a basic
solution?
1. RbClO4
2. NaNO2
3. NH4Cl
36. Consider the following salts. Which one(s) when dissolved in water will produce a neutral
solution?
1. CoBr2
2. (NH4)2S
3. RbI
37. The pH of a solution of Ba(OH)2 is 9.40. What is the molarity of this Ba(OH)2 solution?
[OH-1] = 10(– 9.40) = 4.0 x 10-10 M OH-1
[H3O+1] = 1.0 x 10-14 / 4.0 x 10-10 = 2.5 x 10-5 M H3O+1
pH = – log [2.5 x 10-5] = 4.60
4.0 x 10-10 mole OH-1
1L
1 mole Ca(OH)2
2 mole OH-1
= 2.0 x 10 -10 M Ca(OH)2
38. Calculate the
a. [H3O+1]
b. pH
c. percent dissociation for a 0.50 M HCN solution. (Ka = 4.9 x 10-10)
HCN
+
H2O
I
0.50 M

x
E
0.50 M – x

H3O+1
+
(CN)-1
0
0
+x
+x
x
x
Ka = [H3O+1][(CN)-1] = 4.9 x 10-10 =
x2
[HCN]
0.50 M
x = 1.6 x 10-5 M
[H3O+1] = 1.6 x 10-5 M
pH = - log [1.6 x 10-5] = 4.80
% dissociation = 1.6 x 10-5 M x 100 = 0.032%
0.50 M
39. Calculate the pH of a 0.10 M solution of aqueous ammonia, Kb = 1.8x10-5
NH3
+
H2O
I
0.10 M

x
E
0.10 M x

(NH4)+1
+
(OH)-1
0
0
+x
+x
x
x
Kb = [(NH4)+1][ (OH)-1] = 1.8 x 10-5 =
x2
[NH3]
0.10 M
x = 1.3 x 10-3 M
[(OH)-1] = 1.3 x 10-3 M
Kw = [H3O+1][(OH)-1] = 1.0 x 10-14
[H3O+1] = [1.0 x 10-14]
[1.3 x 10-3]
= 1.3 x 10-12 M
pH = - log [1.3 x 10-12] = 11.89
40. Suppose that 50.00 mL of 0.10 M CH3COOH is neutralized by 50.00 mL of 0.10 M NaOH.
What is the pH of the resulting system?
a. Write the neutralization reaction.
b. How many moles of CH3COO-1 are formed?
c. What is the final volume of the solution?
d. What is the concentration of CH3COO-1?
e. Characterize CH3COO-1 (i.e. weak/strong and acid/base).
f.
Write the reaction of the product and water.
g. Set-up an ICE chart for the reaction and calculate the pH of the solution.