93) Which pair of ions can be separated by the addition of sulfide ion?
A) Ag+ and Cu2+
B) Cu2+ and Bi3+
C) Pb2+ and Ca2+
D) Ca2+ and Ba2+
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.)
94) Which solution has the highest pH?
A) (1)
B) (2)
C) (3)
D) (4)
95) Which solution has the lowest pH?
A) (1)
B) (2)
C) (3)
D) (4)
96) Which solution has the largest percent dissociation of HA?
A) (1)
B) (2)
C) (3)
D) (4)
97) Which of the solutions are buffer solutions?
A) (1) and (2)
B) (1) and (3)
C) (2) and (3)
D) (2) and (4)
98) Which solution has the greatest buffer capacity?
A) (1)
B) (2)
C) (3)
D) (4)
99) 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.)
100) Which solution has the highest pH?
A) (1)
B) (2)
C) (3)
D) (4)
101) Which solution has the lowest pH?
A) (1)
B) (2)
C) (3)
D) (4)
102) Which solution has the largest percent dissociation of HA?
A) (1)
B) (2)
C) (3)
D) (4)
103) Which of these solutions are buffers?
A) (1) and (2)
B) (1) and (3)
C) (1), (2) and (3)
D) All are buffer solutions.
104) Which solution has the greatest buffer capacity?
A) (1)
B) (2)
C) (3)
D) (4)
105) 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.)
106) 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)
107) 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).
108) Which picture represents the solution before the addition of any KOH?
A) (1)
B) (2)
C) (3)
D) (4)
109) Which picture represents the solution before the equivalence point?
A) (1)
B) (2)
C) (3)
D) (4)
110) Which picture represents the solution at the equivalence point?
A) (1)
B) (2)
C) (3)
D) (4)
111) 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).
112) Which picture represents the system halfway to the first equivalence point?
A) (1)
B) (2)
C) (3)
D) (4)
113) Which picture represents the system at the first equivalence point?
A) (1)
B) (2)
C) (3)
D) (4)
114) Which picture represents the system halfway between the first and second equivalence points?
A) (1)
B) (2)
C) (3)
D) (4)
115) Which picture represents the system beyond the second equivalence point?
A) (1)
B) (2)
C) (3)
D) (4)
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116) Which picture represents the system with the highest pH?
A) (1)
B) (2)
C) (3)
D) (4)
117) 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.
118) 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
119) 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
120) 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
The following plot shows two titration curves, each representing the titration of 50.00 mL of 0.100 M
28
acid with 0.100 M NaOH.
121) 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
122) 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
123) 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
124) 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
125) 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.
126) 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
127) Which point a-d represents the HX–/X2– buffer region?
A) point a
B) point b
C) point c
D) point d
128) Which point a-d represents the H2X/HX– buffer region?
A) point a
B) point b
C) point c
D) point d
129) Which point a-d represents the first equivalence point?
A) point a
B) point b
C) point c
D) point d
130) Which point a-d represents the second equivalence point?
A) point a
B) point b
C) point c
D) point d
131) Which point a-d represents pKa1?
A) point a
B) point b
C) point c
D) point d
132) Which point a-d represents pKa2?
A) point a
B) point b
C) point c
D) point d
133) 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
134) 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.
135) 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)