Ionic and net ionic equations Transitional Reasoning Download PDF

Questions

1. 1.

   A chemist monitors an aqueous reaction by slowly adding dilute sulfuric acid, $\text{H}_2\text{SO}_4(aq)$, to an aqueous solution of barium hydroxide, $\text{Ba(OH)}_2(aq)$. A white precipitate of barium sulfate forms simultaneously with liquid water, causing the electrical conductivity of the mixture to drop to near zero at the equivalence point. Which of the following correctly gives the balanced net ionic equation and identifies the spectator ion(s) for this chemical change?

   • A) Net ionic equation: $\text{Ba}^{2+}(aq) + 2\text{OH}^-(aq) + 2\text{H}^+(aq) + \text{SO}_4^{2-}(aq) \rightarrow \text{BaSO}_4(s) + 2\text{H}_2\text{O}(l)$; Spectator ions: None
   • B) Net ionic equation: $\text{H}^+(aq) + \text{OH}^-(aq) \rightarrow \text{H}_2\text{O}(l)$; Spectator ions: $\text{Ba}^{2+}(aq)$ and $\text{SO}_4^{2-}(aq)$
   • C) Net ionic equation: $\text{Ba}^{2+}(aq) + \text{SO}_4^{2-}(aq) \rightarrow \text{BaSO}_4(s)$; Spectator ions: $\text{H}^+(aq)$ and $\text{OH}^-(aq)$
   • D) Net ionic equation: $\text{Ba}^{2+}(aq) + \text{OH}^-(aq) + \text{H}^+(aq) + \text{SO}_4^{2-}(aq) \rightarrow \text{BaSO}_4(s) + \text{H}_2\text{O}(l)$; Spectator ions: None
2. 2.

   A chemistry student analyzes an equimolar neutralization reaction between aqueous hydrofluoric acid, a weak electrolyte represented as $\text{HF}(aq)$, and aqueous potassium hydroxide, $\text{KOH}(aq)$. Because hydrofluoric acid ionizes to an extent of less than 5% in dilute solution, it is formulated in its predominantly molecular state in the total ionic equation. Which of the following accurately identifies the balanced net ionic equation and the spectator ion(s) for this neutralization process?

   • A) Net ionic equation: $\text{H}^+(aq) + \text{OH}^-(aq) \rightarrow \text{H}_2\text{O}(l)$; Spectator ions: $\text{K}^+(aq)$ and $\text{F}^-(aq)$
   • B) Net ionic equation: $\text{HF}(aq) + \text{KOH}(aq) \rightarrow \text{KF}(aq) + \text{H}_2\text{O}(l)$; Spectator ion: None
   • C) Net ionic equation: $\text{H}^+(aq) + \text{KOH}(aq) \rightarrow \text{K}^+(aq) + \text{H}_2\text{O}(l)$; Spectator ion: $\text{F}^-(aq)$
   • D) Net ionic equation: $\text{HF}(aq) + \text{OH}^-(aq) \rightarrow \text{F}^-(aq) + \text{H}_2\text{O}(l)$; Spectator ion: $\text{K}^+(aq)$
3. 3.

   During a chemical analysis of mineral leachate, a student mixes aqueous sodium carbonate, $\text{Na}_2\text{CO}_3(aq)$, with an excess of dilute nitric acid, $\text{HNO}_3(aq)$, and immediately observes vigorous effervescence. To model this gas-evolution process at the particulate level, the student writes the corresponding balanced ionic equations. Which of the following correctly identifies the net ionic equation and the spectator ions for this reaction?

   • A) Net ionic equation: $\text{Na}^+(aq) + \text{NO}_3^-(aq) \rightarrow \text{NaNO}_3(s)$; Spectator ions: $\text{H}^+(aq)$ and $\text{CO}_3^{2-}(aq)$
   • B) Net ionic equation: $2\text{H}^+(aq) + \text{CO}_3^{2-}(aq) \rightarrow \text{H}_2\text{CO}_3(aq)$; Spectator ions: $\text{Na}^+(aq)$ and $\text{NO}_3^-(aq)$
   • C) Net ionic equation: $2\text{H}^+(aq) + \text{CO}_3^{2-}(aq) \rightarrow \text{CO}_2(g) + \text{H}_2\text{O}(l)$; Spectator ions: $\text{Na}^+(aq)$ and $\text{NO}_3^-(aq)$
   • D) Net ionic equation: $\text{Na}_2\text{CO}_3(aq) + 2\text{H}^+(aq) \rightarrow 2\text{Na}^+(aq) + \text{CO}_2(g) + \text{H}_2\text{O}(l)$; Spectator ion: $\text{NO}_3^-(aq)$
4. 4.

   A student investigates the action of an antacid suspension by reacting solid magnesium hydroxide, $\text{Mg(OH)}_2(s)$, with dilute hydrochloric acid, $\text{HCl}(aq)$, producing aqueous magnesium chloride and liquid water. To model the chemical change occurring at the particulate level, the student writes the corresponding balanced ionic equations. Which of the following correctly presents the net ionic equation along with the spectator ion(s) for this reaction?

   • A) Net ionic equation: $\text{H}^+(aq) + \text{OH}^-(aq) \rightarrow \text{H}_2\text{O}(l)$; Spectator ions: $\text{Mg}^{2+}(aq)$ and $\text{Cl}^-(aq)$
   • B) Net ionic equation: $\text{Mg(OH)}_2(s) + 2\text{Cl}^-(aq) \rightarrow \text{MgCl}_2(aq) + 2\text{OH}^-(aq)$; Spectator ion: $\text{H}^+(aq)$
   • C) Net ionic equation: $\text{Mg}^{2+}(aq) + 2\text{OH}^-(aq) + 2\text{H}^+(aq) \rightarrow \text{Mg}^{2+}(aq) + 2\text{H}_2\text{O}(l)$; Spectator ion: None
   • D) Net ionic equation: $\text{Mg(OH)}_2(s) + 2\text{H}^+(aq) \rightarrow \text{Mg}^{2+}(aq) + 2\text{H}_2\text{O}(l)$; Spectator ion: $\text{Cl}^-(aq)$
5. 5.

   An environmental technician treats an industrial wastewater sample containing dissolved lead(II) nitrate, $\text{Pb(NO}_3)_2$, by adding aqueous potassium sulfate, $\text{K}_2\text{SO}_4$, to precipitate toxic lead ions as insoluble lead(II) sulfate. After the dense white solid settles, unreacted ions remain dissolved in the supernatant solution. Which of the following correctly pairs the net ionic equation for this precipitation process with the spectator ions?

   • A) Net ionic equation: $\text{K}^+\text{(aq)} + \text{NO}_3^-\text{(aq)} \rightarrow \text{KNO}_3\text{(s)}$; Spectator ions: $\text{Pb}^{2+}\text{(aq)}$ and $\text{SO}_4^{2-}\text{(aq)}$
   • B) Net ionic equation: $\text{Pb}^{2+}\text{(aq)} + 2\text{NO}_3^-\text{(aq)} + 2\text{K}^+\text{(aq)} + \text{SO}_4^{2-}\text{(aq)} \rightarrow \text{PbSO}_4\text{(s)} + 2\text{K}^+\text{(aq)} + 2\text{NO}_3^-\text{(aq)}$; Spectator ions: none
   • C) Net ionic equation: $\text{Pb}^{2+}\text{(aq)} + \text{SO}_4^{2-}\text{(aq)} \rightarrow \text{PbSO}_4\text{(s)}$; Spectator ions: $\text{K}^+\text{(aq)}$ and $\text{NO}_3^-\text{(aq)}$
   • D) Net ionic equation: $\text{Pb(NO}_3)_2\text{(aq)} + \text{K}_2\text{SO}_4\text{(aq)} \rightarrow \text{PbSO}_4\text{(s)} + 2\text{KNO}_3\text{(aq)}$; Spectator ions: $\text{Pb}^{2+}\text{(aq)}$ and $\text{SO}_4^{2-}\text{(aq)}$