solubility rules

Question

use solubility rules to predict whether or not a precipitation reaction will occur when the following aqueous solutions are mixed. write the molecular and the net ionic equation for each reaction that does occur.

 

A) NaCL(aq) + Pb(NO3)2(aq)=

B) Fe2(SO4)3(aq) + NaBr(aq)=

C) Na2CO3(aq) + BaCl2=

D) CuCl2(aq) + KOH(aq)

Answer 1

Debbie did a nice job answering (A), so here is (B), which is slightly different as you'll see.

Fe2(SO4)3(aq) + 6NaBr(aq) ==> 3Na2SO4(aq) + 2FeBr3(aq) ... balanced molecular equation

 

NOTE:  all reactants and all products are soluble, i.e. aqueous (aq).  Thus, there is NO REACTION, and so a net ionic equation cannot be written per se.

 

Looking at (C)

Na2CO3(aq) + BaCl2(aq) ==> BaCO3(s) + 2NaCl(aq) ... balanced molecular equation

2Na^+(aq) + CO3^2-(aq) + Ba^2+(aq) + 2Cl^-(aq) ==> BaCO3(s) + 2Na^+(aq) + 2Cl^-(aq) ... Total Ion Equation

Ba^2+(aq) + CO3^2-(aq) ==> BaCO3(s) ... Net Ionic Equation

 

You should be able to do (D)

 

Answer 2

Balanced Molecular Equation

2NaCl(aq) + Pb(NO₃)₂(aq) → 2NaNO₃(aq) + PbCl₂(s) 

 

Species in the aqueous phase are all soluble in water. Lead(II) chloride is insoluble in aqueous solution.

 

 

Total Ionic Equation

2Na⁺(aq) + 2Cl^-(aq) + Pb²⁺(aq) + 2NO₃^-(aq) → 2Na⁺(aq) +2NO₃^-(aq) + PbCl₂ (s)  

(remove spectator ions, those ions that appear on both sides of the chemical equation. The remaining species is the net ionic equation.

 

Net Ionic Equation

Pb²⁺(aq) + 2Cl^-(aq) → PbCl₂ (s)

 

*Get a copy of the solubility rules, and check to see which compound is soluble in water. Also you need to get a list of the polyatomic ions and their names. Follow the example above