Net ionic equation answer

Question

When aqueous solutions of potassium carbonate and chromium(II) chloride are combined, solid chromium(II) carbonate and a solution of potassium chloride are formed. The net ionic equation for this reaction is?

Answer 1

Molecular Equation:

K₂CO_3 (aq) + CrCl_{2 (aq)} → Cr₂CO_{3 (s)} + 2KCl _(aq)

 

Since potassium (K) and chlorine (Cl) remain aquous throughout the reaction, they are called "Spectator ions", and are not shown in the final ionic formula:

 

CO₃^2- _(aq) + 2Cr^- _(aq) → CrCO_{3 (s)}

Answer 2

When aqueous solutions of potassium carbonate and chromium(II) chloride are combined, solid chromium(II) carbonate and a solution of potassium chloride are formed

Step one: write the equation

K2CO3(aq) + CrCl2(aq) → CrCO3(s) + KCl(aq)

Step two: balance the equation

K2CO3(aq) + CrCl2(aq) → CrCO3(s) + 2KCl(aq)

Step three: write ions separately

2K⁺ + CO3^2- + Cr²⁺ + 2Cl^- → CrCO3(s) + 2K⁺ + 2Cl^-

Step four: eliminate ions common to both sides

CO32- + Cr2+  → CrCO3(s) 

 

This is the net ionic equation.  the eliminated ions are called spectator ions.