Solubility Rules for Common Ionic Compounds in Water at 25C

Question 1

Group 1A ions

Answer 1

Soluble with no exceptions (exc. top & bottom, i.e. H and Fr)

Question 2

NH₄⁺

Answer 2

Soluble with no exceptions

Question 3

Nitrates (NO₃^-)

Answer 3

Soluble with no exceptions

Question 4

Bicarbonates (HCO₃^-)

Answer 4

Soluble with no exceptions

Question 5

Chlorates (ClO₃^-)

Answer 5

Soluble with no exceptions

Question 6

Halides (Cl^-, Br^-, I^-)

Answer 6

Soluble except when with:

Ag⁺
Hg₂²⁺
Pb²⁺

Question 7

Sulfates (SO₄^2-)

Answer 7

Soluble except when with:

Ag⁺
Ag²⁺
Hg₂²⁺
Pb²⁺
Ca²⁺ (Group 2A)
Sr²⁺ (Group 2A)
Ba²⁺ (Group 2A)

Question 8

Carbonates (CO₃^2-)

Answer 8

Insoluble except when with:

Group 1A ions*
NH₄⁺

*except H and Fr

Question 9

Phosphates (PO₄^3-)

Answer 9

Insoluble except when with:

Group 1A ions*
NH₄⁺

*(except H and Fr)

Question 10

Chromates (CrO₄^2-)

Answer 10

Insoluble except when with:

Group 1A ions*
NH₄⁺

*(except H and Fr)

Question 11

Sulfides (S^2-)

Answer 11

Insoluble except when with:

Group 1A ions*
NH₄⁺
Ca²⁺ (Group 2A)
Sr²⁺ (Group 2A)
Ba²⁺ (Group 2A)

*(except H and Fr)

Question 12

Hydroxides (OH^-)

Answer 12

Insoluble except when with:

Group 1A ions*
NH₄⁺

*(except H and Fr)

Slightly soluble with:

Ca²⁺ (Group 2A)
Sr²⁺ (Group 2A)
Ba²⁺ (Group 2A)

Question 13

Acetates (C₂H₃O₂^-)

Answer 13

Soluble with no exceptions