Question

Write a balanced equation for the precipitation reaction that was used to separate Ba2+ from Ca2+ and Mg2+.

Answer 1

`{\rm Ba^(2+)} \, (aq) + {\rm {SO_4}^(2-)}\, (aq) \to {\rm BaSO_(4)}\, (s)`.

Step-by-step explanation:

Make use of the fact that calcium sulfate
`{\rm CaSO_(4)}` and magnesium sulfate
`{\rm MgSO_(4)}` are much more soluble in water than barium sulfate
`{\rm BaSO_(4)}`.

When sulfate ions
`{\rm {SO_(4)}^(2-)}` are added to dilute solutions containing
`{\rm Ba^(2+)}\, (aq)`,
`{\rm Ca^(2+)}\, (aq)`, and
`{\rm Mg^(2+)}\, (aq)`, precipitation would be visible only in the solution with
`{\rm Ba^(2+)}\, (aq)\!`. Barium sulfate would be the precipitate.

`{\rm Ba^(2+)} \, (aq) + {\rm {SO_4}^(2-)}\, (aq) \to {\rm BaSO_(4)}\, (s)`.

This ionic equation is balanced as it conserves both the atoms and the charges on the ions.