#1: Determine the possible products using the general double displacement equation.
AB + CD
AD + CB
In BaCl2, A is Ba2+,
and B is Cl-. In Na2SO4, C is Na+, and D is
SO42-. The possible products from
the reaction of BaCl2(aq) and Na2SO4(aq) are
BaSO4 and NaCl. (Remember to
consider charge when you determine the formulas for the possible products.)
BaCl2(aq) + Na2SO4(aq) to
BaSO4 and NaCl
Step #2: Predict whether either of the possible products is water insoluble.
According to our
solubility guidelines, most sulfates are soluble, but BaSO4 is an exception. It
is insoluble and would precipitate from the mixture. Because compounds
containing Na+ and Cl- are soluble, NaCl is soluble.
Step #3: Write
the complete equation. (Dont forget to balance the equation.)
BaCl2(aq) + Na2SO4(aq)
BaSO4(s) + 2NaCl(aq)
Step #4: Write the complete ionic equation, describing the aqueous
ionic compounds as ions. Describe the solid as a complete formula.
Ba2+(aq) + 2Cl-(aq) +
+ SO42- (aq)
BaSO4 (s) + 2Na+(aq) + 2Cl-(aq)
The chloride and sodium ions have the same form on each side
of the equation, so they are eliminated as spectator ions.
Ba2+(aq) + SO42-(aq)
This is the reaction used
in industry to form barium sulfate, which is used in paint preparations and in x-ray