Write balanced molecular and net ionic equations for the reaction between hydrobromic acid and potassium hydroxide

Balancing chemical equations is fundamental to understanding chemical reactions. It ensures that the law of conservation of mass is upheld, meaning the number of atoms for each element is equal on both sides of the equation. When writing equations, start by listing all the reactants and products. Then, tally the atoms of each element in the reactants and adjust the coefficients (the numbers in front of the formulas) to match the number of atoms in the products.

For the reaction between hydrobromic acid (HBr) and potassium hydroxide (KOH), we start with the unbalanced molecular equation: \( \text{HBr}(aq) + \text{KOH}(aq) \rightarrow \text{KBr}(aq) + \text{H}_2\text{O}(l) \). We then count the atoms: the equation has already one of each relevant atom on both sides. Thus, our equation is balanced without any further adjustments, satisfying the requirement that mass be conserved in the reaction.

Acid-base reactions, also known as neutralization reactions, involve the reaction of hydrogen ions (\(H^+\)) from the acid with hydroxide ions (\(OH^-\)) from the base to form water (\(H_2O\)). In our example, hydrobromic acid donates a hydrogen ion while potassium hydroxide provides the hydroxide ion.

Following the Arrhenius definition, acids produce hydrogen ions in aqueous solutions, and bases produce hydroxide ions. The net ionic equation for the reaction shown: \(H^+(aq) + OH^-(aq) \rightarrow H_2O(l)\) illustrates the essence of acid-base chemistry — the combination of \(H^+\) and \(OH^-\) to make water, thereby neutralizing the solution. Such reactions are pivotal in various scientific and industrial processes, including titrations and buffering systems.

Spectator ions are ions in a chemical reaction that do not participate in the actual chemical change but are present in the reaction mixture. They remain in solution unchanged and can be observed on both sides of the ionic equation. Identifying spectator ions helps simplify reactions down to their net ionic equations, which display only the species that undergo a chemical change.

For instance, in the reaction between hydrobromic acid and potassium hydroxide, \(K^+\) and \(Br^-\) ions are spectator ions. In the total ionic equation, \(H^+(aq) + Br^-(aq) + K^+(aq) + OH^-(aq) \rightarrow K^+(aq) + Br^-(aq) + H_2O(l)\), these ions appear on both sides without undergoing any chemical transformation. When we omit them, we're left with the net ionic equation: \(H^+(aq) + OH^-(aq) \rightarrow H_2O(l)\). Understanding spectator ions is crucial for simplifying equations and focusing on the actual chemical changes occurring in the reaction.