Chapter 14, Problem 76E

Interpretation Introduction

(a)

Interpretation:

A balanced net ionic equation for the reaction, $\text{Zn}{\left({\text{NO}}_3\right)}_2\left(aq\right)+\text{ NaOH}\left(aq\right)\to \text{Zn}{\left(\text{OH}\right)}_2\left(s\right)+{\text{NaNO}}_3\left(aq\right)$, is to be stated.

Concept introduction:

Chemical reactions are represented by chemical equations. In a chemical equation, the reactants are represented on the left of the arrow while the products are represented on the right of the arrow. The chemical equation representing the reaction in which only the species actually participating are written is termed as an ionic reaction.

Answer to Problem 76E

A balanced net ionic equation for the solution reaction, $\text{Zn}{\left({\text{NO}}_3\right)}_2\left(aq\right)+\text{ NaOH}\left(aq\right)\to \text{Zn}{\left(\text{OH}\right)}_2\left(s\right)+{\text{NaNO}}_3\left(aq\right)$ is shown below.

${\text{Zn}}^{2+}\left(aq\right)+2{\text{OH}}^{-}\left(aq\right)\to \text{Zn}{\left(\text{OH}\right)}_2\left(s\right)$

Explanation of Solution

The chemical reaction is given below.

$\text{Zn}{\left({\text{NO}}_3\right)}_2\left(aq\right)+\text{ NaOH}\left(aq\right)\to \text{Zn}{\left(\text{OH}\right)}_2\left(s\right)+{\text{NaNO}}_3\left(aq\right)$

The balanced reaction is given below.

$\text{Zn}{\left({\text{NO}}_3\right)}_2\left(aq\right)+\text{ 2NaOH}\left(aq\right)\to \text{Zn}{\left(\text{OH}\right)}_2\left(s\right)+2{\text{NaNO}}_3\left(aq\right)$

It is balanced as the number of atoms on each side is the same. $\text{Zn}{\left({\text{NO}}_3\right)}_2$, $\text{NaOH}$, and ${\text{NaNO}}_3$ are strong electrolytes. $\text{Zn}{\left(\text{OH}\right)}_2$ is a weak electrolyte. The balanced nonionic equation given above is converted into a total ionic equation by writing the strong electrolytes in ionized form and the weak electrolytes in nonionized form.

${\text{Zn}}^{2+}\left(aq\right)+2{\text{NO}}_3{}^{-}\left(aq\right)+{\text{ 2Na}}^{+}\left(aq\right)+2{\text{OH}}^{-}\left(aq\right)\to \text{Zn}{\left(\text{OH}\right)}_2\left(s\right)+2{\text{Na}}^{+}\left(aq\right)+2{\text{NO}}_3{}^{-}\left(aq\right)$ In the above total ionic equation, ${\text{Na}}^{+}$ and ${\text{NO}}_3{}^{-}$acts as spectator ions and are removed to obtain the net ionic equation shown below.

${\text{Zn}}^{2+}\left(aq\right)+2{\text{OH}}^{-}\left(aq\right)\to \text{Zn}{\left(\text{OH}\right)}_2\left(s\right)$

Conclusion

A balanced net ionic equation for the given solution reaction has been rightfully stated.

Interpretation Introduction

(b)

Interpretation:

A balanced net ionic equation for the solution reaction, ${\text{MgSO}}_4\left(aq\right){\text{+NH}}_4\text{OH}\left(aq\right)\to \text{Mg}{\left(\text{OH}\right)}_{\text{2}}\left(s\right)+{\left({\text{NH}}_4\right)}_2{\text{SO}}_4\left(aq\right)$ is to be stated.

Concept introduction:

Chemical reactions are represented by chemical equations. In a chemical equation, the reactants are represented on the left of the arrow while the products are represented on the right of the arrow. The chemical equation representing the reaction in which only the species actually participating are written is termed as an ionic reaction.

Answer to Problem 76E

A balanced net ionic equation for the solution reaction, ${\text{MgSO}}_4\left(aq\right){\text{+NH}}_4\text{OH}\left(aq\right)\to \text{Mg}{\left(\text{OH}\right)}_{\text{2}}\left(s\right)+{\left({\text{NH}}_4\right)}_2{\text{SO}}_4\left(aq\right)$ is shown below.

${\text{Mg}}^{2+}{\left(aq\right)}^{+}+2{\text{OH}}^{-}\left(aq\right)\to \text{Mg}{\left(\text{OH}\right)}_{\text{2}}\left(s\right)$

Explanation of Solution

The chemical reaction is given below.

${\text{MgSO}}_4\left(aq\right){\text{+NH}}_4\text{OH}\left(aq\right)\to \text{Mg}{\left(\text{OH}\right)}_{\text{2}}\left(s\right)+{\left({\text{NH}}_4\right)}_2{\text{SO}}_4\left(aq\right)$

The balanced chemical equation is given below.

${\text{MgSO}}_4\left(aq\right){\text{+2NH}}_4\text{OH}\left(aq\right)\to \text{Mg}{\left(\text{OH}\right)}_{\text{2}}\left(s\right)+{\left({\text{NH}}_4\right)}_2{\text{SO}}_4\left(aq\right)$

It is balanced as the number of atoms on each side is the same. ${\text{MgSO}}_4$, ${\text{NH}}_4\text{OH}$ and ${\left({\text{NH}}_4\right)}_2{\text{SO}}_4$ are strong electrolytes. $\text{Mg}{\left(\text{OH}\right)}_{\text{2}}$ is a weak electrolyte. The balanced nonionic equation given above is converted into a total ionic equation by writing the strong electrolytes in ionized form and the weak electrolytes in nonionized form.

${\text{Mg}}^{2+}\left(aq\right)+{\text{SO}}_4{}^{2-}\left(aq\right){\text{+2NH}}_4{}^{+}\left(aq\right)+2{\text{OH}}^{-}\left(aq\right)\to \text{Mg}{\left(\text{OH}\right)}_{\text{2}}\left(s\right)+2{\text{NH}}_4{}^{+}\left(aq\right)+{\text{SO}}_4{}^{2-}\left(aq\right)$ In the above total ionic equation, ${\text{SO}}_4{}^{2-}$, and ${\text{NH}}_4{}^{+}$ act as spectator ions and are removed from the total ionic equation. Therefore, the net ionic equation is given below.

${\text{Mg}}^{2+}{\left(aq\right)}^{+}+2{\text{OH}}^{-}\left(aq\right)\to \text{Mg}{\left(\text{OH}\right)}_{\text{2}}\left(s\right)$

Conclusion

A balanced net ionic equation for the given solution reaction has been rightfully stated.