Chapter 3
51.
(E) The oxidation state (O.S.) is given first, followed by the explanation for its assignment.
(a)
H has an oxidation state of
in its non-metal compounds.
(Remember that the sum of the oxidation states in a neutral
compound equals 0.)
(b)
F has
(c)
Na has
(d)
H has
in its non-metal compounds; that of
(usually). (Remember that the sum of the oxidation states in a
polyatomic ion equals the charge on that ion.)
(e)
52.
in
in its compounds.
in its compounds.
O has
in most of its compounds (especially metal
containing compounds).
(E) The oxidation state of sulfur in each species is determined below. Remember that the
oxidation state of O is
in its compounds. And the sum of the oxidation states in an ion
equals the charge on that ion.
(a)
in
(b)
(d)
in
(e)
in
(c)
in
in S4O62-
Chapter 5
2.
(E)
(a) The best electrical conductor is the solution of the strong electrolyte: 0.10 M NaCl. In
each liter of this solution, there are 0.10 mol
ions and 0.10 mol
ions.
(b) The poorest electrical conductor is the solution of the nonelectrolyte: 0.10 M
. In this solution, the concentration of ions is negligible.
7.
(E)
(a)
(b)
(c)
163
Chapter 5: Introduction to Reactions in Aqueous Solutions
(d)
15.
(M) Determine the amount of
in the solution as it now exists, and the amount of
in
the solution of the desired concentration. The difference in these two amounts is the amount
of
that must be added. Convert this amount to a mass of
in grams.
19.
(E) In each case, each available cation is paired with the available anions, one at a time, to
determine if a compound is produced that is insoluble, based on the solubility rules of
Chapter 5. Then a net ionic equation is written to summarize this information.
(a)
(b) No reaction occurs (all are spectator ions).
(c)
25.
(M)
Mixture
Net Ionic Equation
(a)
(b)
(c)
(upon filtering, KCl (aq) is obtained)
27.
(E) The type of reaction is given first, followed by the net ionic equation.
(a) Neutralization:
(b) No reaction occurs. This is the physical mixing of two acids.
(c) Gas evolution:
(d) Gas evolution:
164
Chapter 5: Introduction to Reactions in Aqueous Solutions
(e) Redox:
36.
(E)
(a)
(b)
(c)
39.
(M)
(a) Oxidation: {
}×2
Reduction:
Net:
(b) Oxidation: {
}×2
Reduction: {
}×3
Net:
(c)
Oxidation: {
}×5
Reduction:
Net:
(d)
(l)
Oxidation: (Ag (s) g Ag+ (aq) + 1 e¯ ) × 3
Reduction: 4 H2O(l) + CrO42- + 3 e¯ g Cr(OH)3(s) + 5 OH Net: 3 Ag(s) + CrO42- + 4 H2O(l) g 3 Ag+(aq) + Cr(OH)3(s) + 5 OH-
49.
(E) The problem is most easily solved with amounts in millimoles.
52.
(E) Titration reaction:
165
Chapter 5: Introduction to Reactions in Aqueous Solutions
54.
(E)
63.
(M)
Conversion pathway approach:
Stepwise approach:
166