The correct chemical formula for baking soda is NaHCO₃. Baking soda is the common name for sodium bicarbonate. Its chemical formula is NaHCO₃. Option A, Na₂CO₃, is sodium carbonate (washing soda). Option C, CaCO₃, is calcium carbonate (limestone). Option D, NaOH, is sodium hydroxide (caustic soda). Understanding common chemical names and formulas is essential.