Aniline, abbreviated fNH2, where f is C6H5, is an important organic base used in the manufacture of dyes. It has a Kb of 4.3 * 10^(-10). In a certain manufacturing process, it is necessary to keep the concentration of fNH3+ (aniline’s conjugate acid, the anilinium ion) below 1.0 * 10^(-9) M in a solution that is 0.10 M in aniline. Find the concentration of NaOH required for this process.

Acid-base equilibrium involves the balance between an acid and its conjugate base in a solution. In this context, aniline (a weak base) can accept a proton to form its conjugate acid, the anilinium ion. The equilibrium can be described using the base dissociation constant (Kb), which quantifies the strength of the base. Understanding this equilibrium is crucial for determining how to control the concentration of the anilinium ion in the solution.

Concentration refers to the amount of a substance in a given volume of solution, typically expressed in molarity (M). In this problem, we need to calculate the concentration of NaOH required to maintain the anilinium ion concentration below a specified limit. The dilution principle states that adding a solute to a solution will change its concentration, which is essential for manipulating the equilibrium of the acid-base reaction in this scenario.

The Henderson-Hasselbalch equation relates the pH of a solution to the pKa of an acid and the ratio of the concentrations of its conjugate base and acid. This equation is particularly useful for buffer solutions, where the pH needs to be maintained within a specific range. In this case, it can help determine the necessary concentration of NaOH to keep the anilinium ion concentration below the desired threshold while considering the initial concentration of aniline.