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CHM 112
Section 1

Homework Assignment #23
Due April 5, 2006 by 8:05 a.m.

Practice (not to be turned in): 16.8, 16.73.

If the following sparingly soluble solids are added to a 1 M solution of nitric acid, will the solubility increase, decrease, or remain the same? Show balanced chemical reactions to justify your conclusions but do not do any detailed calculations. Turn in answers corresponding to the last digit of your Student ID Number AND the last digit ±5, whichever gives a single digit.

(0) Al(OH)3

(1) Cd(OH)2

(2) Co(OH)3

(3) Mg(OH)2

(4) Pb(OH)2

(5) AgC2H3O2

(6) CaC2O4

(7) CdC2O4

(8) CuCN

(9) ZnC2O4



Answers:

In all cases the presence of the strong acid will significantly increase the solubility because of the acid-base reaction between the nitric acid and the basic anion present.

The reactions are given below:

(0) Al(OH)3(s) + 3 HNO3(aq)3 H2O(l) + Al3+(aq) + 3 NO3(aq)

(1) Cd(OH)2(s) + 2 HNO3(aq)2 H2O(l) + Cd2+(aq) + 2 NO3(aq)

(2) Co(OH)3(s) + 3 HNO3(aq)3 H2O(l) + Co3+(aq) + 3 NO3(aq)

(3) Mg(OH)2(s) + 2 HNO3(aq)2 H2O(l) + Mg2+(aq) + 2 NO3(aq)

(4) Pb(OH)2(s) + 2 HNO3(aq)2 H2O(l) + Pb2+(aq) + 2 NO3(aq)

(5) AgC2H3O2(s) + HNO3(aq)CH3COOH(aq) + Ag+(aq) + NO3(aq)

(6) CaC2O4(s) + 2 HNO3(aq)H2C2O4(aq) + Ca2+(aq) + 2 NO3(aq)

(7) CdC2O4(s) + 2 HNO3(aq)H2C2O4(aq) + Cd2+(aq) + 2 NO3(aq)

(8) CuCN(s) + HNO3(aq)HCN(aq) + Cu+(aq) + NO3(aq)

(9) ZnC2O4(s) + 2 HNO3(aq)H2C2O4(aq) + Zn2+(aq) + 2 NO3(aq)