when BaSO₄ dissolves in water it dissociates as follows; BaSO₄ ---> Ba²⁺ + SO₄²⁻ molar solubility of compound is the amount of moles that can be dissolved in 1 L solution if molar solubility of BaSO₄ is x then molar solubility of Ba²⁺ is x and SO₄²⁻ is x. the formula for solubility product constant - ksp is as follows ksp = [Ba²⁺][SO₄²⁻] ksp = (x)(x) ksp = x² and ksp = 1 x 10⁻¹⁰ therefore x² = 1 x 10⁻¹⁰ x = 1 x 10⁻⁵ M the molar solubility of BaSO₄ is 1 x 10⁻⁵ M
