Here's why:
* Iron (III) or Ferric ions (Fe³⁺) are highly reactive. They readily react with water, forming insoluble ferric hydroxide (Fe(OH)₃), a precipitate.
* Bicarbonate ions (HCO₃⁻) are also unstable in acidic solutions. They readily decompose into carbon dioxide (CO₂) and water (H₂O).
Therefore, when you try to combine ferric ions with bicarbonate ions, the following reaction will occur:
Fe³⁺ + 3HCO₃⁻ → Fe(OH)₃(s) + 3CO₂(g) + H₂O(l)
This means, instead of forming a stable ferric bicarbonate, you'll get a precipitate of ferric hydroxide and release carbon dioxide gas.
