Acids and bases practice problems
1) According to Br nsted and Lowry, what is the definition of a base?
2) According to Lewis, what is the definition of an acid?
3) In the following reaction:
BF3 + :NH3
BF3 ·NH3
3)
Boron trifluoride acts as:
A) a Lewis base
B) a Br nsted-Lowry acid
C) an Arrhenius acid
D) a Lewis base
E) a Lewis acid
4) What is meant by the statement that water is amphoteric?
5) In a sample of pure water at 25°C, what are the relative concentrations of the hydronium ion and the hydroxide
ion?
6) The ion-product constant of water is defined as:
7) Which of the following are strong acids?
A) HF
B) C6 H5COOH (benzoic acid)
D) HClO3
C) HClO4
E) H2 C2O4
G) H3 PO4
F) HClO2
H) H2 SO4
8) List all of the common STRONG bases. Indicate which is the least soluble.
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7)
9) Which of the following is a WEAK base?
A) (C2 H5)2 NH
B) NH4+
9)
C) NaOH
D) NH2E) O2-
10) Which of the following acids is the STRONGEST? The acid is followed by its Ka value.
A) HClO2
1.1 × 10-2
B) HCOOH
C) HCN
1.8 × 10-4
4.9 × 10-10
D) HF
E) HNO2
3.5 × 10-4
4.6 × 10-4
11) Which of the following bases is the WEAKEST? The base is followed by its Kb value.
A) (CH3 CH2 )3 N
5.2 × 10-4
B) HOCH2 CH2NH2
3.2 × 10-5
C) NH3
1.8 × 10-5
D) C5 H5N
E) CN-
1.7 × 10-9
10)
11)
2.0 × 10-5
12) Which of the following equations do not hold true at all temperatures (may be more than one
correct answer)?
A) pH = -log[H+]
12)
B) 14.00 = pH + pOH
C) pKa = pH + pOH
D) kw = [H+ ][OH-]
E) [OH] = 10-pOH
13) What molecules are bases in the following reaction:
CH3COOH + H2O
H3O+ + CH3COO-
14) Identify the conjugate acid-base pairs in the following reaction
NH3 (aq) + CH3COOH(aq)
NH4+ (aq) + CH3COO- (aq)
15) The dissociation of hydrocyanic acid occurs by the following reaction. What is the acid ionization constant (Ka)
expression?
HCN(aq) + H2 O(l)
H3O+ (aq) + CN- (aq)
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16) Fill in the following table:
ACID
+
BASE
NH 3
CONJ. ACID
(strength)
+
HNO3
+
H3 O+
+
HCl
+
NH 4 +
+
H2 O
+
H2 O
CONJ. BASE
OH-
(strength)
strong
+
17) What is the conjugate base of H2PO4 ?
18) Which of the following acids will have the strongest conjugate base?
A) HCl
B) HNO3
C) HI
D) HClO4
E) HCN
19) Which of the following ions is the strongest base?
A) F B) HSO4 C) Br-
E) I-
18)
19)
D) NO3-
20) Why is it more difficult for a polyprotic acid to lose its second proton than the first proton (for example
H2 SO4)?
21) What is the [H+] in an aqueous solution where [OH- ] = 1.9 × 10-12 M?
22) What is the pH of a solution with [H+] = 5.9 × 10-9 M?
23) What is the pH of a solution with [OH-] = 7.6 × 10-4 M?
24) Calculate the H+ concentration in a sample of acid rain with a pH of 4.20.
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25) What is the pOH of an aqueous solution with a pH of 3.7?
26) The pH of a 0.050 M solution of perchloric acid is __________.
27) The pH of a 0.0543 M solution of strontium hydroxide is __________.
28) What mass of barium hydroxide should be dissolved in 500.0 mL to yield a solution that has a pH of 11.109?
29) What volume of concentrated HCl solution should be diluted to produce 5.00 L of solution with a pH of 1.50?
Concentrated HCl is 36.0% HCl by mass and has a density of 1.18 g/mL.
30) A saturated solution of calcium hydroxide has a pH of 12.35. How many milligrams of calcium hydroxide are
soluble in 100 mL of solution?
31) What will the pH be if 100.0 mL of 0.105 M HNO3, is mixed with 250.0 mL of 0.0132 M Ba(OH)2 ?
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32) The ion product constant for water at 50 °C is 5.47 × 10- 14. What is the pH of pure water at this temp?
33) What is the pH at 50 °C, if the [H+] is 2.9 x 10-6 M?
34) What is the [OH- ] at 50 °C, if the pH is 4.524?
35) What is the strongest acid and base that can exist in pure liquid methanol?
36) Which of the following is a weak electrolyte?
A) CH2O
B) NH3
C) NaOH
D) HNO3
E) C2 H5OH
36)
37) Which of the following solutions (all 0.1 M) would have the greatest electrical conductivity?
A) Ca(OH)2
B) HCl
C) CH3COOH
37)
38) Which one of the following substances would you expect to be a nonelectrolyte in aqueous
solution?
A) CH3CH2 OH
38)
D) CH3NH2
E) NH4Br
B) HBr
C) CH3COOH
D) KI
E) NH3
39) Why is HF a weak acid, while the other three hydrohalic acids are strong acids?
40) Why is trifluoroacetic acid (CF3COOH) a stronger acid than acetic acid (CH3 COOH)?
A) The trifluoroacetate ion is a stronger conjugate base than the acetate ion.
B) The fluorine push electrons toward the acid-hydrogen bond.
C) The carbon-fluorine bond is stronger than the carbon-hydrogen bond.
D) Fluorine is electron withdrawing, making the OH bond more polar and stabilizing the
conjugate base.
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40)
41) Place the following in order of increasing acid strength.
HBrO2
HBrO3
HBrO
41)
HBrO4
42) Fill in the following table:
Compound
HCl
NaCl
NH 4 Cl
Type of electrolyte
Strong
pH of aqueous solution
Acidic
sodium bisulfate
potassium chlorite
CH3CH2 OH
LiI
sodium fluoride
Fe(OH)3
KNO3
HIO3
43) Would the pH of solid ammonium bicarbonate dissolved in water be acidic, basic, or neutral?
A) acidic
B) basic
C) neutral
D) not enough information
43)
44) What type of solution will each of th of the following oxides form if dissolved in water?
A) SO3(g)
B) Na2O
C) MgO
D) CO2(g)
E) NO2(g)
44)
45) A 32.4 mL sample of H2SO4 requires 20.0 mL of 0.368M NaOH for complete neutralization. What is the
molarity of the acid?
46) A sample of magnesium oxide was completely dissolved in 50.0 mL of 0.183 M hydrochloric acid. Excess acid
was titrated to a phenolphthalein endpoint with 13.4 mL of a 0.105 M solution of sodium hydroxide. What mass
of magnesium oxide dissolved?
47) A sample of battery acid with a density of 1.227 g/mL is to be analyzed for its sulfuric acid content. A 1.00 mL
sample is diluted to 250.0 mL, and 10.00 mL of this diluted acid requires 34.82 mL of 4.680×10-3 M Ba(OH)2 for
its titration. What is the mass percent of sulfuric acid in the battery acid?
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