Determine If A Precipitate Will Form When The Following Solutions Are Mixed. If A Precipitate Forms, Write A Net Ionic! Equation For The Reaction. A. Zinc Sulfate And Potassium Hydroxide B. Nickel(11) Sulfate And Sodium Hydroxide C. Ammonium Carbonate And Cobalt(II) Chloride
The Correct Answer and Explanation is :
To determine if a precipitate will form when two solutions are mixed, we need to consider the solubility rules for the possible products formed from the combination of ions. We’ll evaluate each case to see if any of the products formed are insoluble in water.
A. Zinc Sulfate and Potassium Hydroxide
- Reactants: Zinc sulfate (( \text{ZnSO}_4 )) and potassium hydroxide (( \text{KOH} )).
- Possible products: Zinc hydroxide (( \text{Zn(OH)}_2 )) and potassium sulfate (( \text{K}_2\text{SO}_4 )).
- Zinc hydroxide: Insoluble in water, which means a precipitate will form.
- Potassium sulfate: Soluble in water.
Net Ionic Equation:
[ \text{Zn}^{2+}(aq) + 2\text{OH}^-(aq) \rightarrow \text{Zn(OH)}_2(s) ]
B. Nickel(II) Sulfate and Sodium Hydroxide
- Reactants: Nickel(II) sulfate (( \text{NiSO}_4 )) and sodium hydroxide (( \text{NaOH} )).
- Possible products: Nickel(II) hydroxide (( \text{Ni(OH)}_2 )) and sodium sulfate (( \text{Na}_2\text{SO}_4 )).
- Nickel(II) hydroxide: Insoluble in water, leading to a precipitate.
- Sodium sulfate: Soluble in water.
Net Ionic Equation:
[ \text{Ni}^{2+}(aq) + 2\text{OH}^-(aq) \rightarrow \text{Ni(OH)}_2(s) ]
C. Ammonium Carbonate and Cobalt(II) Chloride
- Reactants: Ammonium carbonate (( \text{(NH}_4)_2\text{CO}_3 )) and cobalt(II) chloride (( \text{CoCl}_2 )).
- Possible products: Cobalt(II) carbonate (( \text{CoCO}_3 )) and ammonium chloride (( \text{NH}_4\text{Cl} )).
- Cobalt(II) carbonate: Insoluble in water, hence a precipitate forms.
- Ammonium chloride: Soluble in water.
Net Ionic Equation:
[ \text{Co}^{2+}(aq) + \text{CO}_3^{2-}(aq) \rightarrow \text{CoCO}_3(s) ]
Explanation
When mixing solutions in a chemical reaction, precipitates form if the products include an insoluble compound according to the solubility rules. Insoluble compounds form a solid in the reaction mixture, indicating a chemical change has occurred. In all three scenarios provided:
- The products that are insoluble and hence form precipitates are zinc hydroxide, nickel(II) hydroxide, and cobalt(II) carbonate. These reactions produce precipitates because their respective hydroxides and carbonate are not soluble in water, unlike the other products such as the sulfates and chlorides of sodium, potassium, and ammonium, which are soluble.
- The net ionic equations focus on the formation of these precipitates, highlighting the movement of ions that lead directly to the formation of the solid. Each equation involves the combination of cations (metal ions) and anions (either hydroxide or carbonate), which come together to form the solid precipitate, simplifying the overall equation to show only the species involved in the formation of the precipitate. This process illustrates the principle behind predicting reaction products in aqueous solutions using solubility rules.