Practice Questions Involving Solubility Rules

First memorize the solubility rules for ionic compounds given in Appendix 11 of your lab manual. You can also click here to reach the rules that I have online at my website.

Put the solubility rules on flashcards and learn them well, ESPECIALLY the first 2 rules about the ones that are ALWAYS soluble.

1. Classify these compounds as soluble or insoluble in water:

a) lead(II) acetate

b) tin(II) sulfate

c) ammonium sulfide

d) strontium chlorate

e) silver(I) bromide

f) sodium phosphate

g) copper(I) carbonate

h) barium sulfate

2. Of the ones above that are soluble, write chemical equations to show what happens when they dissolve in water. An example is shown below:

EXAMPLE: aluminum sulfate

Al₂(SO₄)₃ is soluble. (Sulfates are soluble except for Ba²⁺, Sr²⁺, Pb²⁺ and Hg₂²⁺. Since Al³⁺ is not one of the exceptions, aluminum sulfate must be soluble.)

Note: If you are using NETSCAPE as your browser, the reaction arrow (--> ) may appear as ¾®.

So if you see( ¾¾® ) it is supposed to be an arrow. If you are using INTERNET EXPLORER you should not have this problem.

H₂O

Al₂(SO₄)₃ (s) ¾¾® 2Al³⁺ (aq) + 3SO₄^2– (aq)

Do not peek at the answers until you have written down your answers fully! Be honest to yourself!

Answers:

1) These are the ones that are soluble: a) lead(II) acetate, b) tin(II) sulfate, c) ammonium sulfide, d) strontium chlorate, f) sodium phosphate.

2)

a) Pb(C₂H₃O₂)₂ (s) ¾® Pb²⁺ (aq) + 2 C₂H₃O₂^– (aq)

b) SnSO₄ (s) ¾® Sn²⁺ (aq) + SO₄^2– (aq)

c) (NH₄)₂S (s) ¾® 2 NH₄⁺ (aq) + S^2– (aq)

d) Sr(ClO₃)₂ (s) ¾® Sr²⁺ (aq) + 2 ClO₃^–(aq)

f) Na₃PO₄ (s) ¾® 3 Na⁺ (aq) + PO₄^3–(aq)