21
65) Which metal sulfides can be precipitated from a solution that is 0.01 M in Mn2+, Zn2+, Pb2+ and Cu2+
and 0.10 M in H2S at a pH of 0.50?
A) MnS
B) CuS
C) PbS, CuS
D) ZnS, PbS, CuS
66) A solution may contain the following ions Ag+, Cu2+, Cd2+, Mn2+, Ni2+ and Na+. A white precipitate
formed when 0.10 M NaCl was added and after this was removed the solution was treated with H2S gas
under acidic conditions and no precipitate formed. When the solution was made basic and again treated
with H2S gas a dark colored precipitate formed. If no further tests were made then what conclusions can
you draw?
A) possible ions present Ag+, Mn2+, Ni2+
B) possible ions present Ag+, Mn2+, Ni2+, Na+
C) possible ions present Ag+, Cu2+, Cd2+
D) possible ions present Ag+, Cu2+, Cd2+, Na+
67) A solution may contain the following ions Ag+, Cu2+, Mn2+, Ca2+, and Na+. No precipitate formed
when 0.10 M NaCl was added but a dark colored precipitate formed when H2S was added to an acidic
portion of the solution. After the removal of the solid the solution was made basic and more H2S was
added and a dark precipitate again formed. Treatment of the filtrate with (NH4)2CO3 resulted in a white
precipitate. If no further tests were made then what conclusions can you draw?
A) possible ions present Cu2+, Mn2+, Na+
B) possible ions present Cu2+, Mn2+, Ca2+
C) possible ions present Cu2+, Mn2+, Ca2+, Na+
D) possible ions present Ag+, Cu2+, Mn2+, Ca2+, Na+
The following pictures represent solutions that contain a weak acid HA and/or its potassium salt KA.
Unshaded spheres represent H atoms and shaded spheres represent A– ions. (K+, H3O+, OH–, and
solvent H2O molecules have been omitted for clarity.)
68) Which solution has the highest pH?
A) (1)
B) (2)
C) (3)
D) (4)
69) Which solution has the lowest pH?
A) (1)
B) (2)
C) (3)
D) (4)
70) Which solution has the largest percent dissociation of HA?
A) (1)
B) (2)
C) (3)
D) (4)
71) Which of the solutions are buffer solutions?
A) (1) and (2)
B) (1) and (3)
C) (2) and (3)
D) (2) and (4)
72) Which solution has the greatest buffer capacity?
A) (1)
B) (2)
C) (3)
D) (4)
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73) For which solution(s) is pH = pKa?
A) only solution (1)
B) only solution (2)
C) only solution (3)
D) solutions (1) and (3)
The following pictures represent solutions that contain a weak acid HA (pKa = 5.0) and its potassium salt
KA. Unshaded spheres represent H atoms and shaded spheres represent A– ions. (K+, H3O+, OH–, and
solvent H2O molecules have been omitted for clarity.)
74) Which solution has the highest pH?
A) (1)
B) (2)
C) (3)
D) (4)
75) Which solution has the lowest pH?
A) (1)
B) (2)
C) (3)
D) (4)
76) Which solution has the largest percent dissociation of HA?
A) (1)
B) (2)
C) (3)
D) (4)
77) Which of these solutions are buffers?
A) (1) and (2)
B) (1) and (3)
C) (1), (2) and (3)
D) All are buffer solutions.
78) Which solution has the greatest buffer capacity?
A) (1)
B) (2)
C) (3)
D) (4)
79) For which of these solutions is pH = pKa?
A) All have pH = pKa.
B) (1), (2) and (3)
C) (1) and (4)
D) (2) and (3)
The following pictures represent solutions that contain a weak acid HA (pKa = 5.0) and its potassium salt
KA. Unshaded spheres represent H atoms, black spheres represent oxygen atoms, and shaded spheres
represent A– ions. (K+, H3O+ initially present, OH– initially present and solvent water molecules have
been omitted for clarity.)
80) Which picture represents the equilibrium state of the solution after addition of one H3O+ ion to the
solution shown in picture (1)?
A) (2)
B) (3)
C) (4)
D) (5)
81) Which picture represents the equilibrium state of the solution after addition of one OH– ion to the
solution shown in picture (1)?
A) (2)
B) (3)
C) (4)
D) (5)
The following pictures represent solutions at various points in the titration of a weak acid HA with
aqueous KOH. Unshaded spheres represent H atoms, black spheres represent oxygen atoms, and shaded
spheres represent A– ions. (K+, H3O+ initially present, OH– initially present and solvent water molecules
have been omitted for clarity).
82) Which picture represents the solution before the addition of any KOH?
A) (1)
B) (2)
C) (3)
D) (4)
83) Which picture represents the solution before the equivalence point?
A) (1)
B) (2)
C) (3)
D) (4)
84) Which picture represents the solution at the equivalence point?
A) (1)
B) (2)
C) (3)
D) (4)
85) Which picture represents the solution after the equivalence point?
A) (1)
B) (2)
C) (3)
D) (4)
The following pictures represent solutions at various stages in the titration of a weak diprotic acid H2A
with aqueous KOH. Unshaded spheres represent H atoms, black spheres represent oxygen atoms, and
shaded spheres represent A2– ions. (K+, H3O+ initially present, OH– initially present and solvent water
molecules have been omitted for clarity).
86) Which picture represents the system halfway to the first equivalence point?
A) (1)
B) (2)
C) (3)
D) (4)
87) Which picture represents the system at the first equivalence point?
A) (1)
B) (2)
C) (3)
D) (4)
88) Which picture represents the system halfway between the first and second equivalence points?
A) (1)
B) (2)
C) (3)
D) (4)
89) Which picture represents the system beyond the second equivalence point?
A) (1)
B) (2)
C) (3)
D) (4)
90) Which picture represents the system with the highest pH?
A) (1)
B) (2)
C) (3)
D) (4)
91) Which picture represents the system with the lowest pH?
A) (1)
B) (2)
C) (3)
D) (4)
Use the graphs below to answer the following questions.
92) What is the characteristic pH-titrant curve for the titration of a strong acid by a strong base?
A) A
B) B
C) C
D) D
93) What is the characteristic pH-titrant curve for the titration of a strong base by a strong acid?
A) A
B) B
C) C
D) D
94) What is the characteristic pH-titration curve for the titration of a weak acid by a strong base?
A) A
B) B
C) C
D) D
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The following plot shows two titration curves, each representing the titration of 50.00 mL of 0.100 M acid
with 0.100 M NaOH.
95) Which point a-d represents the equivalence point for the titration of a strong acid?
A) point a
B) point b
C) point c
D) point d
96) Which point a-d represents the equivalence point for the titration of a weak acid?
A) point a
B) point b
C) point c
D) point d
97) At which point a-d is the pKa of the acid equal to the pH?
A) point a
B) point b
C) point c
D) point d
98) Which points a-d represent the half-equivalence point and the equivalence point, respectively, for the
titration of a weak acid?
A) points a and b
B) points a and c
C) points b and d
D) points c and d
99) Which point a-d represents a buffer region?
A) point a
B) point b
C) point c
D) point d
The following plot shows a titration curve for the titration of 1.00 L of 1.00 M diprotic acid H2A with
NaOH.
100) A buffer region is indicated by which point(s) a–d?
A) point a
B) points a and c
C) point b
D) points b and d
101) Which point a-d represents the HX–/X2– buffer region?
A) point a
B) point b
C) point c
D) point d
102) Which point a-d represents the H2X/HX– buffer region?
A) point a
B) point b
C) point c
D) point d
103) Which point a-d represents the first equivalence point?
A) point a
B) point b
C) point c
D) point d
104) Which point a-d represents the second equivalence point?
A) point a
B) point b
C) point c
D) point d
105) Which point a-d represents pKa1?
A) point a
B) point b
C) point c
D) point d
106) Which point a-d represents pKa2?
A) point a
B) point b
C) point c
D) point d
107) What is the pH at the first equivalence point?
A) pH = pKa1
B) pH = 14 – pKa1
C) pH = (pKa1 + pKa2)/2
D) pH = pKa1 + pKa2
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108) The following plot shows a titration curve for the titration of 1.00 L of 1.00 M diprotic acid H2A+
with NaOH. Which point a-d represents the isoelectric point?
A) point a
B) point b
C) point c
D) point d
The following pictures represent solutions of CuS, which may also contain ions other than Cu2+ and S2-
which are not shown. Gray spheres represent Cu2+ ions and dotted spheres represent S2- ions.
109) If solution (1) is a saturated solution of CuS, which of solutions (2)–(4) are unsaturated?
A) only (2)
B) only (3)
C) only (4)
D) (3) and (4)
110) If solution (1) is a saturated solution of CuS, which of solutions (2)–(4) are saturated?
A) (2)
B) (3)
C) (4)
D) None of these
111) If solution (1) is a saturated solution of CuS, which of solutions (2)–(4) are supersaturated?
A) (2)
B) (3)
C) (4)
D) None of these
The following pictures represent solutions of AgCl, which may also contain ions other than Ag+ and Cl–
which are not shown. Gray spheres represent Ag+ ions and dotted spheres represent Cl– ions.
112) If solution (1) is a saturated solution of AgCl, which of solutions (1)-(4) represents the solution after a
small amount of HCl is added and equilibrium is restored?
A) (1)
B) (2)
C) (3)
D) (4)
113) If solution (1) is a saturated solution of AgCl, which of solutions (1)-(4) represents the solution after a
small amount of HNO3 is added and equilibrium is restored?
A) (1)
B) (2)
C) (3)
D) (4)
114) If solution (1) is a saturated solution of AgCl, which of solutions (1)-(4) represents the solution after a
small amount of AgNO3 is added and equilibrium is restored?
A) (1)
B) (2)
C) (3)
D) (4)
39
115) If solution (1) is a saturated solution of AgCl, which of solutions (1)-(4) represents the solution after
a small amount of NH3 is added and equilibrium is restored?
A) (1)
B) (2)
C) (3)
D) (4)
The following pictures represent solutions of CaCO3, which may also contain ions other than Ca2+ and
CO32- which are not shown. Gray spheres represent Ca2+ ions and unshaded spheres represent CO32–
ions.
116) If solution (1) is a saturated solution of CaCO3, which of solutions (1)-(4) represents the solution after
a small amount of NaOH is added and equilibrium is restored?
A) (1)
B) (2)
C) (3)
D) (4)
117) If solution (1) is a saturated solution of CaCO3, which of solutions (1)-(4) represents the solution after
a small amount of HNO3 is added and equilibrium is restored?
A) (1)
B) (2)
C) (3)
D) (4)
118) If solution (1) is a saturated solution of CaCO3, which of solutions (1)-(4) represents the solution after
a small amount of Ca(NO3)2 is added and equilibrium is restored?
A) (1)
B) (2)
C) (3)
D) (4)
119) If solution (1) is a saturated solution of CaCO3, which of solutions (1)-(4) represents the solution after
a small amount of K2CO3 is added and equilibrium is restored?
A) (1)
B) (2)
C) (3)
D) (4)