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When dealing with chemical reactions, it's essential to understand what strong electrolytes are. Strong electrolytes are substances that completely dissociate into ions when dissolved in water. This means they break apart into their constituent ions, enabling them to conduct electricity efficiently in solution.
In our exercise, some examples of strong electrolytes include:

• Hydrobromic acid (\(\mathrm{HBr}\)), which dissociates into \(\mathrm{H^+(aq)}\) and \(\mathrm{Br^-(aq)}\)
• Barium hydroxide (\(\mathrm{Ba(OH)_{2}}\)), which dissociates into \(\mathrm{Ba^{2+}(aq)}\) and two \(\mathrm{OH^{-}(aq)}\)
• Lead(II) nitrate (\(\mathrm{Pb(NO_{3})_{2}}\)), which dissociates into \(\mathrm{Pb^{2+}(aq)}\) and \(2 \mathrm{NO_3^-(aq)}\)

By breaking down in this manner, strong electrolytes allow for the characterization of the chemical species involved in reactions and provide the groundwork for identifying the substances that participate actively in chemical reactions.

The term 'spectator ions' refers to ions that exist in the same form on both the reactant and product sides of a chemical equation. They do not directly participate in the chemical reaction but remain in the solution unchanged. Identifying these ions is crucial when writing net ionic equations because they simplify the equations by omitting them.
For example, in reaction (a) of the exercise, the \(\mathrm{Br^-}\) ion is a spectator ion. It does not participate in forming the product but exists in the same state on both sides. By recognizing and removing such ions, we can focus solely on the ions that undergo change, simplifying our equations and highlighting the essential reactions. This refined representation is what we call the net ionic equation.

Chemical dissociation involves breaking down a compound into its component ions when dissolved in a solution. This process is vital in understanding the behavior of electrolytes in chemical reactions. Each strong electrolyte specified in the reactions dissociates in an aqueous solution, releasing specific ions ready to engage in the reaction.
Let's take a closer look at one example: when \(\mathrm{Ba(OH)_2}\) dissolves in water, it dissociates into \(\mathrm{Ba^{2+}(aq)}\) and \(2\mathrm{OH^{-}(aq)}\). Similarly, \(\mathrm{HBr}\) disassociates into \(\mathrm{H^+(aq)}\) and \(\mathrm{Br^-(aq)}\).Understanding this dissociation process is key to writing both complete and net ionic equations, as it identifies all the ions present in the solution and allows us to pinpoint which participate in the reaction and which remain as spectator ions.

Net ionic reactions aim to show only the chemical species involved in the transformation during a reaction. This requires writing net ionic equations where all spectator ions are excluded, leaving only the ions that actually change during the chemical process.
In the exercise provided, reaction (b) clarifies this process perfectly. After removing spectator ions, the reaction simplifies to \(2\mathrm{H^+(aq)} + 2\mathrm{OH^{-}(aq)} \rightarrow 2\mathrm{H_2O(l)}\). This equation reveals the essential reaction between hydrogen ions and hydroxide ions to form water. This formula represents the net result and fundamental changes occurring during the reaction, offering a clearer understanding of the underlying chemical processes.
By focusing on net ionic reactions, we enhance our understanding of how reactants transform into products, stripping away unnecessary detail and leading to deeper insights into the chemical phenomena at play.