Final answer:
The hydroxide ion (OH-) is produced when a water molecule loses a hydrogen ion and serves to neutralize hydronium ions, resulting in a basic pH solution.
Step-by-step explanation:
The hydroxide ion (OH−) plays a critical role in various chemical reactions. For instance, when a water molecule loses a hydrogen ion (H+), it forms a hydroxide ion. Consequently, this reaction also yields a hydronium ion (H3O+) when another water molecule accepts the hydrogen ion. In the context of the reaction mentioned, the hydroxide ion is responsible for neutralizing hydronium ions, as shown in the equation H3O+ (aq) + OH− (aq) = 2H2O(l). The 1:1 stoichiometry signifies that an excess of hydroxide has been added, which implies more hydroxide ions than initially present hydronium ions. Additionally, the presence of hydroxide ions after weak bases react with water indicates the solution will have a basic pH.
In salt hydrolysis, the hydroxide ion can be produced when a weak Brønsted-Lowry base reacts with water, making the solution basic. The addition of hydroxide ions to a solution ultimately affects the pH by increasing the basicity. This process is crucial in understanding acid-base chemistry and the properties of solutions.