Cliffs AP Chemistry, 3rd Edition

Key Concepts

Equations and relationships that you need to know:

• Solubility Rules

Group Solubility Exceptions

Nitrates NO 3 - All soluble Bi(NO 3 ) 3 , Hg(NO 3 ) 2

Chlorates ClO 3 - All soluble Bi(ClO 3 ) 3 , Hg(ClO 3 ) 2

Perchlorates ClO 4 - All soluble KClO* 4

Acetates CHO 232 - All soluble AgC H O 232

Alkali metal compounds All soluble Some complex (ternary)

Li, Na, K, Rb, Cs alkali metal salts

Ammonium compounds NH 4 + All soluble none

Chlorides Cl– All soluble Those that contain Ag+,

Bromides Br– Hg 2 2+,Pb2+, and PbCl 2 *,

Iodides I– CrCl 3 , BiI 3 , CuI, AuI, AuI 3 ,

PtI 2 , CrBr 2 *, CuBr 2 *, PtBr 4 *,

HgI 2 *

Sulfates SO 42 - Most are soluble SrSO 4 , Sr 2 (SO 4 ) 3 , BaSO 4 ,

PbSO 4 , HgSO 4 , Hg 2 SO 4 ,

CaSO 4 *, Ag 2 SO 4 *,

Cr 2 (SO 4 ) 3 *,Fe 2 (SO 4 ) 3 *

Carbonates Group I, (NH 4 ) 2 CO 3 , All others

CO 32 - CrCO 3

Phosphates PO 43 - Group I, (NH 4 ) 3 PO 4 All others

Sulfites SO 32 - Group I, (NH 4 ) 2 SO 3 All others

Hydroxides OH– Group I, Sr(OH) 2 , All others, Ca(OH) 2 *

Ba(OH) 2 , AuOH

Sulfides S2– Group I, (NH 4 ) 2 S, SrS All others, CaS*

Oxides O2– CaO, SrO, BaO All others, Na 2 O

and K 2 O decompose

in H 2 O

*slightly soluble

Solubility Rules (Abbreviated)

1. All common salts of the Group 1 (IA) elements and ammonium ion are soluble.


2. All common acetates and nitrates are soluble.

Part II: Specific Topics