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Solubility Rules

Solubility Rules for Ionic Substances in Water

Rule 1
Compounds containing NH41+ and group 1A metal ions are soluble.
Rule 2
Compounds containing NO31–, ClO41–, and C2H3O21– are soluble.
Rule 3
Compounds containing Cl1–, Br1–, and I1– are soluble except those of Ag1+, Tl1+, Hg22+, and Pb2+.
Rule 4
Compounds containing SO42– are soluble except those of Ca2+, Sr2+, Ba2+, and Pb2+.
Rule 5
Most other ionic compounds are insoluble in water.