Which compound gives a white precipitate with BaCl₂?

When Na₂CO₃ (sodium carbonate) is added to an aqueous solution of BaCl₂ (barium chloride), a white precipitate of barium carbonate (BaCO₃) is formed:

BaCl₂ (aq) + Na₂CO₃ (aq) → BaCO₃ (s) + 2 NaCl (aq)

This happens because BaCO₃ is insoluble in water, while other compounds behave differently. NaHCO₃ may react slowly but does not form a stable precipitate. NaNO₃ is soluble and does not react with Ba²⁺ ions. Na₂CrO₄ forms a yellow precipitate (BaCrO₄) instead of white.

This reaction is a classic precipitation reaction in inorganic chemistry, used to identify carbonate ions in solutions. It demonstrates solubility rules and helps students understand the behavior of ions in aqueous solutions. The formation of a white precipitate confirms the presence of CO₃²⁻ ions, making sodium carbonate the correct compound.