what kind (ionic or covalent) bond is FeCl2 + Na2CO3? (iron (II) chloride + sodium carbonate).
The correct answer and explanation is:
Correct Answer:
The bonds within FeCl₂ (iron(II) chloride) and Na₂CO₃ (sodium carbonate) are primarily ionic but each compound also contains covalent bonds within certain ions.
When iron(II) chloride reacts with sodium carbonate, both compounds are ionic salts. Iron(II) chloride consists of Fe²⁺ cations and Cl⁻ anions. The attraction between the positively charged iron ion and the negatively charged chloride ions is an electrostatic force that forms an ionic bond. Sodium carbonate consists of Na⁺ cations and CO₃²⁻ anions. The Na⁺ ions and the carbonate anion are also held together by ionic bonds. However, within the carbonate ion (CO₃²⁻), the carbon and oxygen atoms are held together by covalent bonds because the electrons are shared between these nonmetals.
When these two compounds react, they undergo a double displacement reaction. The Fe²⁺ ions combine with the CO₃²⁻ ions to form iron(II) carbonate (FeCO₃), which is usually a precipitate, and the Na⁺ ions combine with Cl⁻ ions to form sodium chloride (NaCl), which stays dissolved in solution if in water. In all cases, the ions are held together by ionic bonds, while the carbonate ion retains its internal covalent bonds.
Overall, the dominant type of bonding in the salts formed and in the reactants is ionic. The exception is the internal bonding in the polyatomic carbonate ion, which is covalent. This dual nature is common in many ionic compounds that contain polyatomic ions such as carbonate, sulfate, nitrate, and phosphate. These ions have covalent bonds within the ion but interact ionically with other ions.
Therefore, FeCl₂ and Na₂CO₃ are both considered ionic compounds because the main bonding force between their cations and anions is ionic attraction, even though the carbonate ion itself has covalent bonds inside it.