Answer
Acid and base used to form this ion, respectively, : $H_3PO_4$ and $Mg(OH)_2$,
Complete ionic equation:
$2H_3PO_4(aq) + 3Mg(OH)_2(s) -- \gt Mg_3(PO_4)_2 + 6H_2O(l) $
Net ionic equation:
$2H_3PO_4(aq) + 3Mg(OH)_2(s) -- \gt Mg_3(PO_4)_2 + 6H_2O(l) $
Work Step by Step
1. Identify the ions of the salt: $(Mg_3(PO_4)_2)$:
$Mg^{2+}$ and $P{O_4}^{3-}$:
To the cation, add hydroxide ions: $Mg(OH)_2$; this is the base.
To the anion, add hydrogen ions: $H_3PO_4$; this is the acid.
2. Now, write the balanced overall equation between them, which is:
$Acid + Base -- \gt Salt + Water$
We already have the salt, so:
$H_3PO_4(aq) + Mg(OH)_2(s) -- \gt Mg_3PO_4(s) + H_2O(l)$
** According to table 3.1, magnesium hydroxide and magnesium phosphate are not soluble in water.
Balance the equation:
$2H_3PO_4(aq) + 3Mg(OH)_2(s) -- \gt Mg_3PO_4(s) + 6H_2O(l)$
3. Write the complete ionic equation.
- For the completely dissociated/ionized compounds, separate them by their ions:
$2H_3PO_4(aq) + 3Mg(OH)_2(s) -- \gt Mg_3PO_4(s) + 6H_2O(l)$
* Phosporic acid is weak, so it is not completely dissociated in water.
4. Remove the repeated ions:
$2H_3PO_4(aq) + 3Mg(OH)_2(s) -- \gt Mg_3PO_4(s) + 6H_2O(l)$
This is the net ionic equation.
