AP Chemistry Solubility Rules

Alkali Metal Ions

Always Soluble

NH4+

Always Soluble

NO3-

Always Soluble

ClO3-

Always Soluble

ClO4-

Always Soluble

C2H3O2-

Always Soluble

Cl-

Soluble except Ag+, Pb2+, Hg2^2+ (AP/H)

Br-

Soluble except Ag+, Pb2+, Hg2^2+ (AP/H)

I-

Soluble except Ag+, Pb2+, Hg2^2+ (AP/H)

F-

Soluble except Ca2+, Sr2+, Ba2+, Pb2+ (CBS-PM)

SO4^2-

Soluble except Ca2+, Sr2+, Ba2+, Pb2+ (CBS/PBS)

O2-

Insoluble except NH4+ and alkali metals Ca2+, Sr2+, Ba2+ (CBS) somewhat soluble

OH-

Insoluble except NH4+ and alkali metals Ca2+, Sr2+, Ba2+ (CBS) somewhat soluble

CO3^2-

Insoluble except alkali metals and NH4+

PO4^3-

Insoluble except alkali metals and NH4+

S2-

Insoluble except alkali metals and NH4+

SO3^2-

Insoluble except alkali metals and NH4+

C2O4^2-

Insoluble except alkali metals and NH4+

CrO4^2-

Insoluble except alkali metals and NH4+

H₂CO_{3 —>}

CO₂ + H₂O

H₂SO_{3 —>}

SO_{2 +} H₂O

HNO_{2 —>}

NO + NO₂ + H_2O

NH₄OH —>

NH₃ + H₂O

H₂S

H₂S

HCN

HCN

Weak Acids

esp. HC₂H₃O₂ and HF