Why no current in potentiometry?

In potentiometry, no current flows because the measurement is based on the voltage difference between two electrodes in a solution, rather than the flow of charge. The system is designed to maintain a high impedance, allowing for the measurement of potential without drawing significant current, which could alter the concentration of ions in the solution and affect the accuracy of the measurement. Thus, potentiometric measurements focus on the equilibrium state of the electrochemical potential.