Solubility Guidelines (Insoluble)

Question 1

CO₃⁻²

Answer 1

All carbonates are insoluble except group I elements and NH₄ ⁺

Question 2

CrO₄⁻²

Answer 2

All chromates are insoluble except group I elements and NH₄⁺, CaCrO₄, SrCrO₄

Question 3

OH⁻

Answer 3

All hydroxides are insoluble except group I elements, Ba(OH)₂, Sr(OH)₂, and Ca(OH)₂

Question 4

PO₄⁻³

Answer 4

All phosphates are insoluble except group I elements and NH₄⁺

Question 5

SO₃⁻²

Answer 5

All sulfites are insoluble except group I elements and NH₄⁺

Question 6

S⁻²

Answer 6

All sulfides are insoluble except group I elements, group II elements, and NH₄⁺

Question 7

F⁻

Answer 7

All fluorides are insoluble except group I and NH₄⁺

Question 8

Metallic oxides (MgO, FeO)

Answer 8

All metallic oxides are insoluble except group I elements and NH₄⁺