4. Assume that an aqueous solution of a cation, represented as a red sphere, is allowed to mix with a solution of an anion, represented as a yellow sphere. Three possible outcomes are represented by boxes (1)–(3):
4.24
Which outcome corresponds to each of the following reactions?
(a) 2 Na+(aq) + CO32(aq)
(b) Ba2+(aq) + CrO42-(aq)
(c) 2 Ag+(aq) + SO32(aq)

5. Assume that an aqueous solution of a cation, represented as a blue sphere, is allowed to mix with a solution of an anion, represented as a green sphere, and that the following result is obtained:
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Which combinations of cation and anion, chosen from the following lists, are compatible with the observed results? Explain.
Cations: Na+, Ca2+, Ag+, Ni2+
Anions: Cl, Ca32, CrO42, NO3

6. 4.26
Assume that an aqueous solution of OH, represented as a blue sphere, is allowed to mix with a solution of an acid HnA, represented as a red sphere. Three possible outcomes are depicted by boxes (1)–(3), where the green spheres represent On, the anion of the acid:
Which outcome corresponds to each of the following reactions?
(a) HF + OH H2O + F
(b) H2SO3 + 2 OH H2O + SO32
(c) H3PO3 + 2 OH H2O + PO43

7. 4.27
The concentration of an aqueous solution of NaOCl (sodium hypochlorite; the active ingredient in household bleach) can be determined by a redox titration with iodide ion in acidic solution:
Ocl(aq) + 2 I(aq) + 2 H+(aq) Cl–(aq) + I2(aq) + H2O(l)
Assume that the blue spheres in the buret represent I ions, the red spheres in the flask represent Ocl ions, the concentration of the I ions in the buret is M, and the volumes in the buret and the flask are identical. What is the concentration of NaOCl in the flask? What percentage of the I solution in the buret must be added to the flask to react with all the OCl ions?

8. Assume that the conductivity of a solution depends on the total concentration of dissolved ions and that you measure the conductivity of three different solutions while carrying out titration procedures:
(a) Begin with 1.00 L of M KCl, and titrate by addition of M AgNO3.
(b) Begin with 1.00 L of M HF, and titrate by addition of M KOH.
(c) Begin with 1.00 L of M BaCl2 and titrate by addition of M Na2SO4.
Which of the following graphs corresponds to which titration?
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9. Based on the positions in the periodic table, which of the following reactions would you expect to occur?
(a) Red+ + Green Red + Green+
(b) Blue + Green Blue+ + Green
(c) Red + Blue Red+ + Blue
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