What defines a Lewis Base in terms of pH?

A Lewis Base is defined as a substance that can donate an electron pair to form a covalent bond. While the definition of a Lewis Base is not strictly dependent on pH, in practical terms, many basic substances are associated with a pH above 7 on the pH scale. This is because Lewis Bases often increase the concentration of hydroxide ions (OH-) in solution, leading to an increase in pH.

For example, when substances such as sodium hydroxide (NaOH) dissolve in water, they dissociate to produce hydroxide ions, which raises the pH above 7, indicating a basic solution. In contrast, solutions with a pH below 7 are considered acidic and do not typically exhibit the properties of Lewis Bases, which are alkaline. Thus, the characterization of Lewis Bases in this context aligns with the understanding that they correlate with a higher pH due to their electron-donating abilities and subsequent increase in hydroxide ion concentration in solutions.