## Chemistry: The Molecular Science (5th Edition)

Published by Cengage Learning

# Chapter 3 - Chemical Reactions - Questions for Review and Thought - Topical Questions - Page 148c: 43b

#### 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.

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