Part 2: Metathesis Reactions
AX + BY AY + BX
Reactants (15 Drops each)
No.
Observation
Equations
Molecular
1
2
Copper (II) sulfate + sodium carbonate
Copper (II) sulfate + Barium chloride
Net ionic eq.
CuSO4 (aq) + Na2CO3 (aq)→ CuCO3 (S)+ Na2SO4 (aq)
eq.
Net ionic
Cu2+ (aq) + CO32 (aq) → CuCO3 (5)↓
eq.
Molecular
CuSO4 (aq) + BaCl2 (aq) →
eq.
Molecular
Nickel chloride + sodium carbonate
3
eq. Net ionic
NiCl2 (aq) + Na2CO3 (aq) →
eq.
Molecular
Na2CO3 (aq) + 2HCl (aq) →
4
Sodium carbonate + hydrochloric acid
Ammonium chloride + sodium hydroxide
5
6
Sodium acetate + hydrochloric acid
eq.
Net ionic
eq.
Molecular
NH4Cl (aq) + NaOH (aq) →
eq.
Net ionic
eq.
Molecular
CH3COONa (aq) + HCI →
eq. Net ionic
eq.
Potassium chloride + sodium nitrate
7
Molecular
KCI (aq) + NaNO3 (aq) →
eq.
Net ionic
eq.
The Correct Answer and Explanation is :
The provided reactions are all examples of metathesis reactions, where the cations and anions of two ionic compounds exchange places to form new products. These reactions are also known as double displacement reactions. Let’s go through each one systematically, providing the molecular and net ionic equations along with a brief explanation.
1. Copper (II) sulfate + Sodium carbonate
Molecular Equation: CuSO4(aq)+Na2CO3(aq)→CuCO3(s)+Na2SO4(aq)\text{CuSO}_4(aq) + \text{Na}_2\text{CO}_3(aq) \rightarrow \text{CuCO}_3(s) + \text{Na}_2\text{SO}_4(aq) Net Ionic Equation: Cu2+(aq)+CO32−(aq)→CuCO3(s)\text{Cu}^{2+}(aq) + \text{CO}_3^{2-}(aq) \rightarrow \text{CuCO}_3(s) This reaction involves copper (II) sulfate and sodium carbonate. Copper (II) carbonate forms as a precipitate, which is the driving force of the reaction. The copper ions combine with carbonate ions to form insoluble copper carbonate.
2. Copper (II) sulfate + Barium chloride
Molecular Equation: CuSO4(aq)+BaCl2(aq)→CuCl2(aq)+BaSO4(s)\text{CuSO}_4(aq) + \text{BaCl}_2(aq) \rightarrow \text{CuCl}_2(aq) + \text{BaSO}_4(s) Net Ionic Equation: Ba2+(aq)+SO42−(aq)→BaSO4(s)\text{Ba}^{2+}(aq) + \text{SO}_4^{2-}(aq) \rightarrow \text{BaSO}_4(s) Here, barium sulfate (BaSO₄) forms as a precipitate because barium sulfate is insoluble in water. The copper ions and chloride ions do not participate in the formation of a precipitate and remain in solution.
3. Nickel chloride + Sodium carbonate
Molecular Equation: NiCl2(aq)+Na2CO3(aq)→NiCO3(s)+NaCl(aq)\text{NiCl}_2(aq) + \text{Na}_2\text{CO}_3(aq) \rightarrow \text{NiCO}_3(s) + \text{NaCl}(aq) Net Ionic Equation: Ni2+(aq)+CO32−(aq)→NiCO3(s)\text{Ni}^{2+}(aq) + \text{CO}_3^{2-}(aq) \rightarrow \text{NiCO}_3(s) Nickel carbonate (NiCO₃) precipitates from the solution as nickel (II) ions react with carbonate ions.
4. Sodium carbonate + Hydrochloric acid
Molecular Equation: Na2CO3(aq)+2HCl(aq)→2NaCl(aq)+H2O(l)+CO2(g)\text{Na}_2\text{CO}_3(aq) + 2\text{HCl}(aq) \rightarrow 2\text{NaCl}(aq) + \text{H}_2\text{O}(l) + \text{CO}_2(g) Net Ionic Equation: CO32−(aq)+2H+(aq)→H2O(l)+CO2(g)\text{CO}_3^{2-}(aq) + 2\text{H}^+(aq) \rightarrow \text{H}_2\text{O}(l) + \text{CO}_2(g) In this reaction, sodium carbonate reacts with hydrochloric acid to form sodium chloride, water, and carbon dioxide gas. The carbonate ions react with hydrogen ions to produce carbonic acid, which quickly decomposes to release CO₂ gas.
5. Ammonium chloride + Sodium hydroxide
Molecular Equation: NH4Cl(aq)+NaOH(aq)→NH3(g)+NaCl(aq)+H2O(l)\text{NH}_4\text{Cl}(aq) + \text{NaOH}(aq) \rightarrow \text{NH}_3(g) + \text{NaCl}(aq) + \text{H}_2\text{O}(l) Net Ionic Equation: NH4+(aq)+OH−(aq)→NH3(g)+H2O(l)\text{NH}_4^+(aq) + \text{OH}^-(aq) \rightarrow \text{NH}_3(g) + \text{H}_2\text{O}(l) Ammonium chloride reacts with sodium hydroxide, producing ammonia gas (NH₃), water, and sodium chloride. The ammonium ion reacts with hydroxide ions to form ammonia and water.
6. Sodium acetate + Hydrochloric acid
Molecular Equation: CH3COONa(aq)+HCl(aq)→CH3COOH(aq)+NaCl(aq)\text{CH}_3\text{COONa}(aq) + \text{HCl}(aq) \rightarrow \text{CH}_3\text{COOH}(aq) + \text{NaCl}(aq) Net Ionic Equation: CH3COO−(aq)+H+(aq)→CH3COOH(aq)\text{CH}_3\text{COO}^-(aq) + \text{H}^+(aq) \rightarrow \text{CH}_3\text{COOH}(aq) Sodium acetate reacts with hydrochloric acid, forming acetic acid (CH₃COOH) and sodium chloride.
7. Potassium chloride + Sodium nitrate
Molecular Equation: KCl(aq)+NaNO3(aq)→KNO3(aq)+NaCl(aq)\text{KCl}(aq) + \text{NaNO}_3(aq) \rightarrow \text{KNO}_3(aq) + \text{NaCl}(aq) Net Ionic Equation: There are no net ionic changes because both potassium chloride and sodium nitrate are soluble in water, and no precipitate or gas forms. Hence, it is a simple exchange of ions.
Conclusion:
In these reactions, the metathesis mechanism is key to their progression. Often, the formation of a precipitate, the evolution of a gas, or the formation of a weak electrolyte like water drives the reaction to completion.