Solubility Rules

Alkali Metals (Group 1A)

universally soluble

NH₄⁺ (ammonium)

universally soluble

Nitrates (NO₃^-)

universally soluble

Acetates (C₂H₃O₂^-/CH₃COO^-)

universally soluble

Chlorates (ClO₃^-)

universally soluble

Cl^-

soluble except with Ag⁺, Hg₂²⁺, Pb²⁺

Br^-

soluble except with Ag⁺, Hg₂²⁺, Pb²⁺

I^-

soluble except with Ag⁺, Hg₂²⁺, Pb²⁺

Sulfates (SO₄²⁻)

soluble except with Ag⁺, Hg₂²⁺, Pb²⁺, and group 2A from Ca down, including Ca

Carbonates (CO₃²⁻)

not soluble except with NH₄⁺ and all alkali metals (group 1A)

Phosphates (PO₄³⁻)

not soluble except with NH₄⁺ and all alkali metals (group 1A)

Chromates (CrO₄²⁻)

not soluble except with NH₄⁺ and all alkali metals (group 1A)

Hydroxides (OH^-)

not soluble except with NH₄⁺, all alkali metals (group 1A), and group 2A from Ca down

Oxides (O²⁻)

not soluble except with NH₄⁺, all alkali metals (group 1A), and group 2A from Ca down

- does not physically exist in water but can be derived from other soluble compounds (see below)

𝘕𝘰𝘯-𝘮𝘦𝘵𝘢𝘭 𝘰𝘹𝘪𝘥𝘦𝘴 𝘣𝘦𝘤𝘰𝘮𝘦 𝘢𝘤𝘪𝘥𝘴 𝘢𝘯𝘥 𝘮𝘦𝘵𝘢𝘭 𝘰𝘹𝘪𝘥𝘦𝘴 𝘣𝘦𝘤𝘰𝘮𝘦 𝘩𝘺𝘥𝘳𝘰𝘹𝘪𝘥𝘦 𝘣𝘢𝘴𝘦𝘴 (－𝘖𝘏) 𝘪𝘯 𝘸𝘢𝘵𝘦𝘳:

• Na₂O(𝘴) + H₂O(𝘭) → 2NaOH(𝘢𝘲)

• CO₂(𝘨) + H₂O(𝘭) → H₂CO³(𝘢𝘲)

Sulfides (S²⁻)

not soluble except with NH₄⁺, all alkali metals (group 1A), and all of group 2A

NH₄OH (ammonia water)

- may be produced as a result of a reaction

- unstable and decomposes into ammonia gas (NH₃) and water

- pretty much doesn't exist (see reaction below)

NH₄Cl(𝘢𝘲) + NaOH(𝘢𝘲) → NH₄OH(𝘢𝘲) + NaCl(𝘢𝘲)

⇒ NH₄Cl(𝘢𝘲) + NaOH(𝘢𝘲) → NH₃ (𝘨) + H₂O(𝘭) + NaCl(𝘢𝘲)