Potentiometry is a technique used to measure the potential voltage of an electrochemical cell, which can be related to the concentration of a specific ion in the solution. In this case, we are interested in the concentration of chloride ions Cl- in a 0.1 M sodium chloride NaCl solution.In a sodium chloride solution, NaCl dissociates into sodium ions Na+ and chloride ions Cl- . The dissociation can be represented by the following equation:NaCl Na+ + Cl-Since the stoichiometry of the reaction is 1:1, the concentration of chloride ions will be equal to the concentration of sodium chloride. Therefore, in a 0.1 M NaCl solution, the concentration of chloride ions Cl- will also be 0.1 M.