Solubility rules step by step

What are solubility rules?

Guidelines to predict the solubility of ionic compounds in water.

Rule 1: Nitrates

All nitrates (NO₃⁻) are soluble in water.

True or false: Chlorides are always soluble.

False, because AgCl, PbCl₂, and Hg₂Cl₂ are exceptions.

Fill in the blank: Most _____ salts are soluble.

alkali metal (Group 1) salts.

What is the solubility of sulfates?

Most sulfates (SO₄²⁻) are soluble, except BaSO₄, PbSO₄, and CaSO₄.

Difference between soluble and insoluble

Soluble: dissolves in water; Insoluble: does not dissolve significantly.

What compounds are insoluble?

Most carbonates (CO₃²⁻) and phosphates (PO₄³⁻) except for alkali metals.

Rule 3: Hydroxides

Most hydroxides (OH⁻) are insoluble, except those of alkali metals and Ba(OH)₂.

Which ion makes chloride soluble?

The presence of alkali metals like Na⁺.

True or false: All sulfides are soluble.

False, because most sulfides are insoluble except those of Group 1 and 2 metals.

What are the exceptions to phosphate solubility?

Phosphates are generally insoluble, except with alkali metals and ammonium.

Fill in the blank: Salts of _____ are typically soluble.

ammonium (NH₄⁺).

Comparison: Soluble vs. insoluble compounds

Soluble compounds dissolve significantly; insoluble compounds do not.

True or false: All alkali metals are soluble.

True, because all salts of alkali metals are soluble.

What is a common exception to sulfate solubility?

Barium sulfate (BaSO₄) is insoluble.

Fill in the blank: _____ compounds are generally insoluble.

Metal carbonates.

What are some soluble salts containing sulfate?

Calcium sulfate (CaSO₄) is less soluble than other sulfates.

Rule 4: Carbonates

Most carbonates (CO₃²⁻) are insoluble except for alkali metal carbonates.