Exam                                                                                                       Name___________________________________
MULTIPLE   CHOICE.
Choose   the   one   alternative   that   best   completes   the   statement   or   answers   the   question.
1) In   the   gas   phase   reaction   below,   NH3   is   acting   as   a(n)   __________   base   but   not as   a(n)   __________ base.
1)
H
+
.
.
N    +    H
+
 | 
|
→ N
 | 
H   H   H H   H   H
A) Lewis,   Arrhenius
B) Lewis,   Br ∅ nsted
-
Lowry
C) Arrhenius,   Lewis
D) Br ∅ nsted Lowry,   Lewis
E) Arrhenius,   Br ∅ nsted Lowry
2) A   0.0035
M   aqueous   solution   of   a   particular   compound   has   pH
=
2.46.
The   compound   is
__________.
A) a   strong   base
B) a   strong   acid
C) a   salt
D) a   weak   acid
E) a   weak   base
2)
3) Of   the   following,   which   is   the   strongest   acid?
A) HIO2
B) HIO
C) HIO4
D) HIO3
E) The   acid   strength   of   all   of   the   above   is   the   same.
3)
4) A   0.1
M   solution   of   __________   has   a   pH   of   7.0.
A) Na2S B) NaF C) NH4Cl D) NaNO3 E) KF
5) HA   is   a   weak   acid.
Which   equilibrium   corresponds   to   the   equilibrium   constant   Kb   for   A
-
?
A) HA   (aq)    +    OH
-
(aq)
B) A
C) A
-
-
(aq)
(aq)
+
+
OH
-
(aq)
H3O
+
(aq)
D) A
-
(aq)
+
H2O   (l)
HOA2
-
(aq)
H2O
HA
(l)
(aq)
+
+
H
HA   (aq)
+
OH
+
(aq)
H2O
-
(l)
(aq)
E) HA   (aq)    +    H2O   (l)       H2A
+
(aq)    +    OH
-
(aq)
4)
5)
6) Which   solution   below   has   the   highest   concentration   of   hydroxide   ions?
A) pH
=
9.82
B) pH
=
7.93
C) pH
=
3.21
D) pH
=
12.6
E) pH
=
7.00
6)
1

7) The   molar   concentration   of   hydronium   ion   in   pure   water   at   25 °C   is   __________.
A) 1.00
B) 1.0
×   10
-
7
C) 7.00
D) 0.00
E) 1.0
×
10
14
8) Which   one   of   the   following   is   the   weakest   acid?
A) HCN   (Ka   =   4.9
×   10
-
10)
B) Acetic   acid   (Ka   =   1.8
×   10
-
5)
C) HClO   (Ka
=
3.0
×
10
8)
D) HNO2   (Ka
=
4.5
×
10
4)
E) HF   (Ka
=
6.8
×
10
4)
9) A   substance   that   is   capable   of   acting   as   both   an   acid   and   as   a   base   is   __________.
A) autosomal
B) conjugated
C) saturated
D) miscible
E) amphoteric
10) Which   of   the   following   aqueous   solutions   has   the   lowest   [OH
-
]?
A) a   1   ×   10
-
4   M   solution   of   HNO3
B) a   solution   with   a   pOH   of   12.0
C) pure   water
D) a   1   ×   10
-
3   M   solution   of   NH4Cl
E) a   solution   with   a   pH   of   3.0
11) Of   the   following   substances,   an   aqueous   solution   of   __________   will   form   basic solutions.
NaHS       Cu(NO3)2       KHCO3       NaF
A) NaF   only
B) NaHS   ,   Cu(NO3)2
C) KHCO3,   NaHS
D) NaF,   KHCO3
E) NaHS,   KHCO3   and   NaF
12) Which   one   of   the   following   statements   regarding   Kw is   false?
A) Kw   is   known   as   the   ion   product   of   water.
B) pKw   is   14.00
at   25°C
C) Kw   changes   with   temperature.
D) The   value   of   Kw   is   always   1.0
×   10
14.
E) The   value   of   Kw   shows   that   water   is   a   weak   acid.
2
7)
8)
9)
10)
11)
12)

13) Of   the   acids   in   the   table   below,   __________   is   the   strongest   acid.
Acid Ka
HOAc 1.8
×
10
5
HCHO2 1.8
×   10
-
4
HClO
HF
3.0
×   10
-
8
6.8
×   10
4
A) HF
B) HCHO2
C) HClO
D) HOAc
E) HOAc   and   HCHO2
14) A   Br ∅ nsted
-
Lowry   acid   is   defined   as   a   substance   that   __________.
A) increases    Ka   when   placed   in   H2O
B) acts   as   a   proton   acceptor
C) increases   [OH
-
]   when   placed   in   H2O
D) acts   as   a   proton   donor
E) decreases   [H
+
]   when   placed   in   H2O
15) Calculate   the   molarity   of   hydroxide   ion   in   an   aqueous   solution   that   has   a   pOH   of   5.33.
A) 2.1
×   10
9
B) 8.7
×   10
-
14
C) 5.3
×   10
14
D) 8.67
E) 4.7
×   10
-
6
16) The   pH   of   an   aqueous   solution   at   25.0°C   is   10.66.
What   is   the   molarity   of   H
+
in   this   solution?
A) 1.1
×
10
13
B) 4.6
×   1010
C) 4.6
×
10
4
D) 2.2
×   10
-
11
E) 3.3
17) Ammonia   is   a   __________.
A) weak   acid
B) strong   acid
C) strong   base
D) weak   base
E) salt
18) Classify   the   following   compounds   as   weak   bases   (W)   or   strong   bases   (S): ammonia
A) W   W   S flouride
B) S   W   W
ion sodium
C) S   S   S
hydroxide
D) W   S    S E) W   S   W
3
13)
14)
15)
16)
17)
18)

19) Using   the   data   in   the   table,   which   of   the   conjugate   bases   below   is   the   weakest   base?
Acid Ka
HOAc 1.8
×
10
5
HCHO2 1.8
×   10
-
4
HClO 3.0
×   10
-
8
HF 6.8
×   10
4
A) CHO2
-
B) OAc
C) F
-
-
D) ClO
-
E) OAc
-
and   CHO2
-
20) The   acid
dissociation   constant   at   25.0°C   for   hypochlorous   acid   (HClO)   is   3.0
×
10
equilibrium,   the   molarity   of   H3O
+
in   a   0.010
M   solution   of   HClO   is   __________.
8.
At
A) 4.76
B) 0.010
C) 2.00
D) 1.7
×   10
-
5
E) 5.8
×
10
10
SHORT   ANSWER.
Write   the   word   or   phrase   that   best   completes   each   statement   or   answers   the   question.
21) What   is   the   pH   of   a   sodium   acetate   solution   prepared   by   adding   0.820
grams acetate   to   100.0
ml   of   water   at   25.0°C?
The   Ka   at   25.0°C   for   acetic   acid   is   1.8
of   sodium
×
10
5.
21)
22) 22) What   is   the   pH   of   a   sodium   formate   solution   prepared   by   adding   0.680
grams   of   sodium formate   to   100.0
ml   of   water   at   25.0°C?
The   K a   at   25.0°C   for   formic   acid   is   1.8
×   10
-
4.
23) A   solution   of   formic   acid   is   3.0%   dissociated   at   25.0°C.
What   is   the   original   concentration
(in   M)   of   the   formic   acid   solution?
The   Ka   at   25.0°C   for   formic   acid    is   1.8
×
10
4.
23)
24) A   solution   of   ammonia   is   2.0%   ionized   at   25.0°C.
What   was   the   original   concentration   (in
M)   of   the   ammonia   solution?
The   Kb   at   25.0°C   for   ammonia   is   1.8
×   10
5.
24)
19)
20)
25) A   solution   of   acetic   acid   is   2.0%   dissociated   at   25.0°C.
What   was   the   original   concentration
(in   M)   of   the   acetic   acid   solution?
The   Ka   at   25.0°C   for   acetic   acid   is   1.8
×   10
-
5.
25)
MULTIPLE   CHOICE.
Choose   the   one   alternative   that   best   completes   the   statement   or   answers   the   question.
26) What   is   the   conjugate   acid   of   NH3?
A) NH2
+
B) NH3 C) NH4OH D) NH3
+
E) NH4
+
26)
4

27) What   is   the   conjugate   base   of   OH
-
?
A) H3O
+
B) O2 C) O
-
D) H2O E) O2
-
27)
28) The   pH   of   a   0.10
M   solution   of   a   weak   base   is   9.82.
What   is   the   Kb for   this   base?
A) 6.6
×   10
4 B) 2.0
×   10
5 C) 4.4
×   10
8 D) 8.8
×   10
8
29) The   conjugate   acid   of   HSO4
A) H
+
-
is
B) HSO3
__________.
+
C) HSO4
+
D) H2SO4
30) The   Ka   for   HCN   is   4.9
×
10
-
A) 2.0
×   10
5
B) 4.9
×   10
-
24
C) 4.0
×   10
6
10.
What   is   the   value   of   Kb   for   CN
-
?
D) 4.9
×   104
E) 2.0
×   109
E) 2.1
×
E) SO42
31) What   is   the   pH   of   an   aqueous   solution   at   25.0
°C   that   contains   3.98
×
10
9
M   hydroxide   ion?
A) 5.60
B) 3.98
C) 9.00
D) 8.40
E) 7.00
32) The   Ka   for   formic   acid   (HCO2H)   is   1.8
×
10
4.
What   is   the   pH   of   a   0.35
M   aqueous   solution   of sodium   formate   (NaHCO2)?
A) 11.64
B) 4.26
C) 3.39
D) 8.64
E) 5.42
10
-
4
28)
29)
30)
31)
32)
33) Determine   the   pH   of   a   0.35
M   aqueous   solution   of   CH3NH2 (methylamine).
The   Kb   of methylamine   is   4.4
×   10
4.
A) 10.00
B) 1.96
C) 12.09
D) 13.24
E) 3.86
33)
34) The   acid
dissociation   constants   of   phosphoric   acid   (H3PO4)   are   Ka1
=
7.5
×
10
3,
Ka2
=
6.2
×
10
8, and   Ka3
=
4.2
×
10
13
at   25.0°C.
What   is   the   pH   of   a   2.5
M   aqueous   solution   of   phosphoric   acid?
A) 0.88
B) 2.51
C) 0.13
D) 0.40
E) 1.82
34)
35) A   0.15
M   aqueous   solution   of   the   weak   acid   HA   at   25.0
°C   has   a   pH   of   5.35.
The   value   of   Ka   for   HA is   __________.
A) 1.8
×
10
5
B) 1.3
×   10
10
C) 7.1
×
10
9
D) 3.0
×   10
5
E) 3.3
×
104
35)
TRUE/FALSE.
Write  ʹ T ʹ  if   the   statement   is   true   and  ʹ F ʹ  if   the   statement   is   false.
36) When   the   proton   in   the   COOH   group   in   an   amino   acid   is   transferred   to   the   N H2 group   of   that same   amino   acid   molecule,   a   zwitterion   is   formed.
36)
5

37) An   acid   containing   the   COOH   group   is   called   a   carbo oxy   acid.
38) In   the   reaction
BF3
+
F
-
→
BF4
-
BF3   acts   as   a   Br ∅ nsted Lowry   acid.
39) A   Lewis   acid   is   an   electron
pair   acceptor,   and   a   Lewis   base   is   an   electron
pair   donor.
40) The   simplest   amino   acid   is   glycine.
37)
38)
39)
40)
6

Answer   Key
Testname:   CH16PRAC
1) A
2) B
3) C
4) D
5) D
6) D
7) B
8) A
9) E
10) B
11) E
12) D
13) A
14) D
15) E
16) D
17) D
18) A
19) C
20) D
21) 8.87
22) 8.46
23) 0.20
24) 0.045
25) 0.045
26) E
27) E
28) C
29) D
30) A
31) A
32) D
33) C
34) A
35) B
36) TRUE
37) FALSE
38) FALSE
39) TRUE
40) TRUE
7