NaOH, or sodium hydroxide, impacts the solubility of benzoic acid in water through a process known as neutralization. Benzoic acid is a weak acid that partially ionizes in water to produce benzoate ions and hydrogen ions. In a basic solution, such as one containing NaOH, the hydroxide ions from the NaOH can react with the hydrogen ions produced by benzoic acid, leading to the formation of water.
This reaction effectively reduces the concentration of free hydrogen ions in the solution, shifting the equilibrium of the benzoic acid dissociation to the right. As a result, more benzoic acid can ionize to produce benzoate ions, which are more soluble in water compared to the neutral benzoic acid molecule.
So, in summary, the addition of NaOH increases the solubility of benzoic acid in water by promoting the formation of benzoate ions, thus making the compound more soluble in a basic environment.