Question

Write balanced molecular and net ionic equations for the reactions of (a) hydrochloric acid with nickel; (b) dilute sulfuric acid with iron; (c) hydrobromic acid with magnesium; (d) acetic acid, \(\mathrm{CH}_{3} \mathrm{COOH}\), with zinc.

Short answer

1. Hydrochloric acid with nickel: Molecular: \(Ni(s) + 2HCl(aq) \rightarrow NiCl_{2}(aq) + H_{2}(g)\) Net ionic: \(Ni(s) + 2 H^{+}(aq) + 2 Cl^{-}(aq) \rightarrow Ni^{2+}(aq) + 2 Cl^{-}(aq) + H_{2}(g)\) 2. Dilute sulfuric acid with iron: Molecular: \(2 Fe(s) + 6 H_{2}SO_{4}(aq) \rightarrow Fe_{2}(SO_{4})_{3}(aq) + 6 H_{2}(g)\) Net ionic: \(2 Fe(s) + 6 H^{+}(aq) + 6 SO_{4}^{2-}(aq) \rightarrow 2 Fe^{3+}(aq) + 6 H_{2}(g) + 6 SO_{4}^{2-}(aq)\) 3. Hydrobromic acid with magnesium: Molecular: \(Mg(s) + 2 HBr(aq) \rightarrow MgBr_{2}(aq) + H_{2}(g)\) Net ionic: \(Mg(s) + 2 H^{+}(aq) + 2 Br^{-}(aq) \rightarrow Mg^{2+}(aq) + 2 Br^{-}(aq) + H_{2}(g)\) 4. Acetic acid with zinc: Molecular: \(Zn(s) + 2 CH_{3}COOH(aq) \rightarrow Zn(C_{2}H_{3}O_{2})_{2}(aq) + H_{2}(g)\) Net ionic: \(Zn(s) + 2 CH_{3}COOH(aq) \rightarrow Zn^{2+}(aq) + 2 CH_{3}COO^{-}(aq) + H_{2}(g)\)

Step-by-step solution

1. Hydrochloric acid with nickel - Molecular equation

When hydrochloric acid reacts with nickel, it forms nickel (II) chloride (NiCl2) and hydrogen gas (H2). The equation for this reaction is: \(Ni(s) + 2HCl(aq) \rightarrow NiCl_{2}(aq) + H_{2}(g)\)

1. Hydrochloric acid with nickel - Net ionic equation

The net ionic equation includes only the ions that undergo a change during the reaction. The spectator ions remain the same in reactants and products. In this case, the net ionic equation is the same as the molecular equation because all the ions are involved in the reaction. \(Ni(s) + 2 H^{+}(aq) + 2 Cl^{-}(aq) \rightarrow Ni^{2+}(aq) + 2 Cl^{-}(aq) + H_{2}(g)\)

2. Dilute sulfuric acid with iron - Molecular equation

When dilute sulfuric acid reacts with iron, it forms iron (III) sulfate (Fe2(SO4)3) and hydrogen gas (H2). The equation for this reaction is: \(2 Fe(s) + 6 H_{2}SO_{4}(aq) \rightarrow Fe_{2}(SO_{4})_{3}(aq) + 6 H_{2}(g)\)

2. Dilute sulfuric acid with iron - Net ionic equation

The net ionic equation includes only the ions that undergo a change during the reaction. In this case, the net ionic equation is the same as the molecular equation because all the ions are involved in the reaction. \(2 Fe(s) + 6 H^{+}(aq) + 6 SO_{4}^{2-}(aq) \rightarrow 2 Fe^{3+}(aq) + 6 H_{2}(g) + 6 SO_{4}^{2-}(aq)\)

3. Hydrobromic acid with magnesium - Molecular equation

When hydrobromic acid reacts with magnesium, it forms magnesium bromide (MgBr2) and hydrogen gas (H2). The equation for this reaction is: \(Mg(s) + 2 HBr(aq) \rightarrow MgBr_{2}(aq) + H_{2}(g)\)

3. Hydrobromic acid with magnesium - Net ionic equation

The net ionic equation includes only the ions that undergo a change during the reaction. In this case, the net ionic equation is the same as the molecular equation because all the ions are involved in the reaction. \(Mg(s) + 2 H^{+}(aq) + 2 Br^{-}(aq) \rightarrow Mg^{2+}(aq) + 2 Br^{-}(aq) + H_{2}(g)\)

4. Acetic acid with zinc - Molecular equation

When acetic acid reacts with zinc, it forms zinc acetate (Zn(C2H3O2)2) and hydrogen gas (H2). The equation for this reaction is: \(Zn(s) + 2 CH_{3}COOH(aq) \rightarrow Zn(C_{2}H_{3}O_{2})_{2}(aq) + H_{2}(g)\)

4. Acetic acid with zinc - Net ionic equation

The net ionic equation includes only the ions that undergo a change during the reaction. In this case, acetic acid is a weak electrolyte, so it does not dissociate completely into its ions. Therefore, we will treat it as an entire molecule. The net ionic equation is the same as the molecular equation because all the ions are involved in the reaction. \(Zn(s) + 2 CH_{3}COOH(aq) \rightarrow Zn^{2+}(aq) + 2 CH_{3}COO^{-}(aq) + H_{2}(g)\)