What is the net ionic equation of 2H+ + SO42- + Ca2+ + 2I- → CaSO4 + 2H+ + 2I-?
A. 2H+ + SO42- + Ca2+ → CaSO4 + 2H+
B. H2SO4(aq) + CaI2(aq) → CaSO4(s) + 2HI(aq)
C. SO42- + Ca2+ → CaSO4
D. H+ + SO42- + Ca2+ + 2I- → CaSO4 + H+ + 2I-
The Correct Answer and Explanation is :
The correct net ionic equation for the reaction (2H^+ + SO_4^{2-} + Ca^{2+} + 2I^- → CaSO_4 + 2H^+ + 2I^-) is:
C. (SO_4^{2-} + Ca^{2+} → CaSO_4)
Explanation:
- Understanding Ionic Equations:
Ionic equations represent the dissociation of compounds in solution. In the full ionic equation provided, we have both reactants and products, some of which are soluble ions and some that precipitate or form a solid. - Dissociation of Compounds:
In this equation:
- (CaI_2) and (H_2SO_4) are strong electrolytes and dissociate completely in solution:
- (CaI_2(aq) → Ca^{2+}(aq) + 2I^-(aq))
- (H_2SO_4(aq) → 2H^+(aq) + SO_4^{2-}(aq))
- Identifying Spectator Ions:
Spectator ions are ions that appear in the same form on both sides of the equation and do not participate in the actual reaction. In this case:
- (2H^+) and (2I^-) are present on both sides of the reaction, meaning they do not affect the net reaction.
- Net Ionic Equation:
By eliminating the spectator ions from the full ionic equation, we can derive the net ionic equation. The remaining ions that participate in the formation of the solid (CaSO_4) are:
- (SO_4^{2-}) and (Ca^{2+}).
- Finalizing the Net Ionic Equation:
Thus, when we combine the ions that react, we obtain:
[
SO_4^{2-} + Ca^{2+} → CaSO_4(s)
]
This represents the formation of the precipitate calcium sulfate (CaSO4) from the sulfate ions and calcium ions, which is the essence of the net ionic equation.
In summary, the net ionic equation focuses solely on the species that undergo a chemical change, simplifying the representation to highlight the formation of the solid precipitate.