The Medical College - Page 42
110.
If 5
10
–13 moles of sodium
hydroxide are dis-
solved in the above one liter aqueous solution
of
1
10
–12 moles of
benzoic acid, the pH will be:
A.
between 4 and 5.
B.
between 5 and 6.
C.
between 6 and 7.
D.
between 7 and 8.
Passage VII (Questions 111–115)
A solution of AgNO3 (1
10
–6 molar) is
prepared.
To this is added K2CrO4 until precipitation of
Ag2CrO4
begins. The Ksp
of Ag2CrO4 is 9
10
–12.
111.
The precipitate begins at a K2CrO4 concentration
of about:
A.
1
10
–6.
C.
1
10
–1.
B.
1
10
–3.
D.
1
10
1.
112.
Addition of NaCl will bring about:
A.
additional precipitation of
Ag2CrO4.
B.
a reaction that will dissolve the
Ag2CrO4
precipitate.
C.
precipitation of AgCl only if its
Ksp is
exceeded.
D.
A and C.
113.
Increasing the temperature will
usually:
A.
bring about more complete
precipitation.
B.
change the Ksp.
C.
change the formula of the
precipitate.
D.
not be easily accomplished until
ongoing
precipitation is complete.
114.
If the Ksp's of AgBr, AgCl, and AgI are
respec-
tively 7.7
10
–13,
1.56
10
–10, and
1.5
10
–16,
the addition of the sodium salt of which of
these
halides would first bring about precipitation
of
an insoluble salt?
A.
NaBr
B.
NaCl
C.
NaI
D.
all about the same (within a factor of
10)
115.
If the sodium salts of the 3 halides in
question
114 were added to a concentration that is
one-
half of that needed to bring about
precipitation
of that particular silver salt, the result
would be:
A.
precipitation of only the least soluble
silver
halide.
B.
percipitation of part of each of the three
sil-
ver halides.
C.
precipitation of a portion of the two
least
soluble silver halides.
D.
no precipitation.
Passage VIII (Questions
116–120)
Many metals react with oxygen to form
oxides.
Some of these oxides, such as
Na2O, CaO, and
SrO,
react with water to form basic solutions.
(These oxides
are called basic oxides or basic
anhydrides.)
Many nonmetals can react with oxygen to
form
oxides as well. These nonmetal oxides, however,
react
with water to form acidic solutions. Thus, they
are
called acid anhydrides.
116.
Phosphorus would be expected to react
with
oxygen to form an oxide that will:
A.
react with water to form an acidic
solution.
B.
react with water to form a basic
solution.
C.
react with water to form a neutral
solution.
D.
not react with water.
117.
Nitrogen will react with oxygen to form an
oxide
(N2O5) that
will:
A.
react with water to form an acidic
solution.
B.
react with water to form a basic
solution.
C.
react with water to form a neutral
solution.
D.
not react with water.
118.
One mole of Ca will react with oxygen to
form
an oxide that will react with water to
form:
A.
one mole of acid in solution.
B.
one mole of base in solution.
C.
two moles of acid in solution.
D.
two moles of base in solution.
119.
The solution in the question above would
require
for neutralization.
A.
one mole of HCl
B.
one mole of NaOH
C.
two moles of HCl
D.
two moles of NaOH
120.
Burning of coal (without use of
sufficient
scrubbers) in the production of electricity
is
believed by many to be a major cause of
"acid
rain." If so, this is most likely because of
the
production of:
A.
oxides of sulfur.
B.
carbon dioxide.
C.
carbon monoxide.
D.
sodium oxide.
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