Identify the spectator ion(s) in the equation
CaCl2(aq) + Na2CO3(aq) =CaCO3(s) + NaCl(aq).
1. Ca2+, CO2−3
2. Ca2+, Cl−
3. Na+, Cl−
4. Na+, CO2−
A spectator ion is an ion that is equally present on both sides of the reaction. In order to figure this out we first have to balance the reaction:
CaCl2(aq) + Na2CO3 (aq) –> CaCO3 (s) +2 NaCl (aq)
Now recognize that compounds that are aqueous are dissolved in water as ions. This is true of all compounds except for CaCO3 it is insoluble in water (you can look this up but it’s given to you that’s why there is an (s) next to it) So now break up the equation into ions.
Ca2(+) + 2Cl(-) + 2Na(+) + CO3 (2-) –> CaCO3 (s) + 2Na(+) + 2Cl(-)
Any ion that is on both sides of the reaction is a spectator ion. These are Cl- and Na+. The answer is therefore option 3.
Write out the entire chemical equation with all species present interior the reacting equipment lined. while the equation is finished, a spectator ion is an ion that seems on the two components of the reaction without substitute. eg Mg(s) + 2H(+) + 2 Cl(-) –> Mg(2+)(aq) + H2(g) + 2 Cl(-) the chlorine ions are spectator ions coz they dont substitute