In the initial state, the center-chamber NaCl solution is at near-neutral pH. In our specific system, hydroxide crossover from the alkaline negolyte (pH 13) is faster than proton crossover from the acidic posolyte (about pH 3). Thus, over time, the pH of the center chamber drifts to higher values. Higher center pH will increase the hydroxide exchange rate through the AEM, and any exchanged hydroxide ion entering the acidic chamber will be neutralized by a proton. Thus, the net effect of hydroxides exchanged across the AEM is the loss of protons in acidic chamber. Eventually, the center chamber pH will reach steady state (Fig ), at which point the net flux of protons and the net flux of hydroxide into the center chamber are equal.