A Brønsted-Lowry acid is simply a compound that supplies a hydrogen ion in a reaction. A Brønsted-Lowry base on the other hand, is a compound that accepts a hydrogen ion in a reaction.
Thus, the Brønsted-Lowry definitions of an acid and a base focus on the movement of hydrogen ions in a reaction, rather than on the production of hydrogen ions and hydroxide ions in an aqueous solution.
The hydroxide ion in these compounds accepts a proton (Hydrogen ion) from acids to form water: This means shydroxides functions as a base.
Each mole of barium sulfate releases equal moles of barium ions and sulfate ions. Let the concentration of one substance be x. Thus: Ksp = [Ba⁺²][SO₄⁻²] 1.1 x 10⁻¹⁰ = (x)(x) x = 1.05 x 10⁻⁵