Answer
Acid and base used to form this ion, respectively: $HCl$ and $Ca(OH)_2$,
Complete ionic equation:
$2H^+(aq) + 2Cl^-(aq) + Ca^{2+}(aq) + 2OH^-(aq) -- \gt Ca^{2+}(aq) + 2Cl^-(aq) + 2H_2O(l) $
Net ionic equation:
$2H^+(aq) + 2OH^-(aq) -- \gt 2H_2O(l) $
Work Step by Step
1. Identify the ions of the salt: $(CaCl_2)$:
$Ca^{2+}$ and 2 $Cl^-$:
To the cation, add a hydroxide ion: $Ca(OH)_2$; this is the base.
To the anion, add a hydrogen ion: $HCl$; 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:
$2HCl(aq) + Ca(OH)_2(aq) -- \gt CaCl_2(aq) + H_2O(l)$
Balance it:
$2HCl(aq) + Ca(OH)_2(aq) -- \gt CaCl_2(aq) + 2H_2O(l)$
3. Write the complete ionic equation.
- For the completely dissociated/ionized compounds, separate them by their ions:
$2H^+(aq) + 2Cl^-(aq) + Ca^{2+}(aq) + 2OH^-(aq) -- \gt Ca^{2+}(aq) + 2Cl^-(aq) + 2H_2O(l) $
* $Ca(OH)_2$ is a strong base, and $CaCl_2$ is soluble according to the table 3.1.
** HCl is a strong acid, so it is completely dissociated.
4. Remove the repeated ions:
$2H^+(aq) + 2OH^-(aq) -- \gt 2H_2O(l) $
This is the net ionic equation.
