Reactions of Salt Mixtures (1). Reactants Observation(s) Equations a. FeCl3 + CoCl2 Ionic: Net ionic: b. CoCl2 + Na2CO3 Ionic: Net ionic: c. Na2CO3 + CuSO4 Ionic: Net ionic: d. CuSO4 + Na3PO4 Ionic: Net ionic: e. Na3PO4 + NiCl2 Ionic: Net ionic:
The Correct Answer and Explanation is:
Let’s break down the reactions one by one.
a. FeCl3 + CoCl2
Ionic Equation: Fe3+(aq)+3Cl−(aq)+Co2+(aq)+2Cl−(aq)→Fe3+(aq)+Co2+(aq)+5Cl−(aq)Fe^{3+}(aq) + 3Cl^{-}(aq) + Co^{2+}(aq) + 2Cl^{-}(aq) \rightarrow Fe^{3+}(aq) + Co^{2+}(aq) + 5Cl^{-}(aq)Fe3+(aq)+3Cl−(aq)+Co2+(aq)+2Cl−(aq)→Fe3+(aq)+Co2+(aq)+5Cl−(aq)
Net Ionic Equation:
There is no observable reaction here since no precipitate or gas is formed, so the net ionic equation would be: No reactionNo\ reactionNo reaction
b. CoCl2 + Na2CO3
Ionic Equation: Co2+(aq)+2Cl−(aq)+2Na+(aq)+CO32−(aq)→CoCO3(s)+2Na+(aq)+2Cl−(aq)Co^{2+}(aq) + 2Cl^{-}(aq) + 2Na^{+}(aq) + CO3^{2-}(aq) \rightarrow CoCO3(s) + 2Na^{+}(aq) + 2Cl^{-}(aq)Co2+(aq)+2Cl−(aq)+2Na+(aq)+CO32−(aq)→CoCO3(s)+2Na+(aq)+2Cl−(aq)
Net Ionic Equation: Co2+(aq)+CO32−(aq)→CoCO3(s)Co^{2+}(aq) + CO3^{2-}(aq) \rightarrow CoCO3(s)Co2+(aq)+CO32−(aq)→CoCO3(s)
This forms cobalt(II) carbonate (CoCO₃) as a precipitate, a common reaction when metal salts react with carbonate ions.
c. Na2CO3 + CuSO4
Ionic Equation: 2Na+(aq)+CO32−(aq)+Cu2+(aq)+SO42−(aq)→2Na+(aq)+SO42−(aq)+CuCO3(s)2Na^{+}(aq) + CO3^{2-}(aq) + Cu^{2+}(aq) + SO4^{2-}(aq) \rightarrow 2Na^{+}(aq) + SO4^{2-}(aq) + CuCO3(s)2Na+(aq)+CO32−(aq)+Cu2+(aq)+SO42−(aq)→2Na+(aq)+SO42−(aq)+CuCO3(s)
Net Ionic Equation: Cu2+(aq)+CO32−(aq)→CuCO3(s)Cu^{2+}(aq) + CO3^{2-}(aq) \rightarrow CuCO3(s)Cu2+(aq)+CO32−(aq)→CuCO3(s)
This forms copper(II) carbonate (CuCO₃), which is a precipitate in this reaction.
d. CuSO4 + Na3PO4
Ionic Equation: Cu2+(aq)+SO42−(aq)+3Na+(aq)+PO43−(aq)→CuPO4(s)+3Na+(aq)+SO42−(aq)Cu^{2+}(aq) + SO4^{2-}(aq) + 3Na^{+}(aq) + PO4^{3-}(aq) \rightarrow CuPO4(s) + 3Na^{+}(aq) + SO4^{2-}(aq)Cu2+(aq)+SO42−(aq)+3Na+(aq)+PO43−(aq)→CuPO4(s)+3Na+(aq)+SO42−(aq)
Net Ionic Equation: Cu2+(aq)+PO43−(aq)→CuPO4(s)Cu^{2+}(aq) + PO4^{3-}(aq) \rightarrow CuPO4(s)Cu2+(aq)+PO43−(aq)→CuPO4(s)
Copper phosphate (CuPO₄) precipitates from the solution in this reaction.
e. Na3PO4 + NiCl2
Ionic Equation: 3Na+(aq)+PO43−(aq)+Ni2+(aq)+2Cl−(aq)→3Na+(aq)+2Cl−(aq)+NiPO4(s)3Na^{+}(aq) + PO4^{3-}(aq) + Ni^{2+}(aq) + 2Cl^{-}(aq) \rightarrow 3Na^{+}(aq) + 2Cl^{-}(aq) + NiPO4(s)3Na+(aq)+PO43−(aq)+Ni2+(aq)+2Cl−(aq)→3Na+(aq)+2Cl−(aq)+NiPO4(s)
Net Ionic Equation: Ni2+(aq)+PO43−(aq)→NiPO4(s)Ni^{2+}(aq) + PO4^{3-}(aq) \rightarrow NiPO4(s)Ni2+(aq)+PO43−(aq)→NiPO4(s)
Nickel phosphate (NiPO₄) precipitates out as a solid in this reaction.
Summary:
In all these reactions, metal salts (usually divalent or trivalent metal ions) react with anions like carbonate (CO₃²⁻), phosphate (PO₄³⁻), or carbonate to form precipitates. The key step is identifying which ions form an insoluble compound (precipitate), and the net ionic equation simplifies to the ions that are directly involved in the formation of the precipitate.
