What is the net ionic equation for the reaction between lead nitrate and potassium chloride
The Correct Answer and Explanation is:
To write the net ionic equation for the reaction between lead(II) nitrate and potassium chloride, we first need to understand the reaction itself and the relevant steps involved.
Step 1: Write the balanced molecular equation
The reactants are lead(II) nitrate (Pb(NO₃)₂) and potassium chloride (KCl). These two compounds react in an aqueous solution, and when mixed, they undergo a double displacement reaction.
The molecular equation for the reaction is:Pb(NO3)2(aq)+2KCl(aq)→PbCl2(s)+2KNO3(aq)\text{Pb(NO}_3\text{)}_2(aq) + 2\text{KCl}(aq) \rightarrow \text{PbCl}_2(s) + 2\text{KNO}_3(aq)Pb(NO3)2(aq)+2KCl(aq)→PbCl2(s)+2KNO3(aq)
In this reaction, lead(II) chloride (PbCl₂) is formed as a solid precipitate, while potassium nitrate (KNO₃) remains dissolved in the aqueous solution.
Step 2: Write the full ionic equation
When compounds are dissolved in water, they dissociate into their respective ions. So, we need to break up the soluble ionic compounds into ions.Pb2+(aq)+2NO3−(aq)+2K+(aq)+2Cl−(aq)→PbCl2(s)+2K+(aq)+2NO3−(aq)\text{Pb}^{2+}(aq) + 2\text{NO}_3^-(aq) + 2\text{K}^+(aq) + 2\text{Cl}^-(aq) \rightarrow \text{PbCl}_2(s) + 2\text{K}^+(aq) + 2\text{NO}_3^-(aq)Pb2+(aq)+2NO3−(aq)+2K+(aq)+2Cl−(aq)→PbCl2(s)+2K+(aq)+2NO3−(aq)
Step 3: Identify the spectator ions
Spectator ions are ions that do not participate in the reaction and remain unchanged on both sides of the equation. In this case, the potassium ions (K+\text{K}^+K+) and nitrate ions (NO3−\text{NO}_3^-NO3−) are spectator ions.
Step 4: Write the net ionic equation
After canceling the spectator ions, we are left with the following net ionic equation:Pb2+(aq)+2Cl−(aq)→PbCl2(s)\text{Pb}^{2+}(aq) + 2\text{Cl}^-(aq) \rightarrow \text{PbCl}_2(s)Pb2+(aq)+2Cl−(aq)→PbCl2(s)
This equation shows that lead(II) ions (Pb2+\text{Pb}^{2+}Pb2+) and chloride ions (Cl−\text{Cl}^-Cl−) combine to form solid lead(II) chloride (PbCl₂), which precipitates out of the solution.
Conclusion
The net ionic equation represents only the ions involved in the formation of the precipitate. In this case, the lead(II) ion and chloride ion come together to form PbCl₂ as a solid, with the other ions (K⁺ and NO₃⁻) remaining in solution as spectator ions.
