PH of neutrality is not exactly 7 (25 °C), although this is a good approximation in most cases. Neutrality is defined as the condition where [H] = [OH] (or the activities are equal). Since self-ionization of water holds the product of these concentration [H]×[OH] = K, it can be seen that at neutrality [H] = [OH] = , or pH = pK/2. pK is approximately 14 but depends on ionic strength and temperature, and so the pH of neutrality does also. Pure water and a solution of NaCl in pure water are both neutral, since dissociation of water produces equal numbers
Impedance–pH monitoring symptoms in a statistically meaningful manner. Patients with a positive impedance–pH monitoring test may benefit from acid-reduction therapy such as fundoplication surgery or endoscopic fundoplication techniques. Impedance–pH monitoring Impedance–pH monitoring is a technique used in the diagnosis of gastroesophageal reflux disease (GERD), by monitoring both impedance and pH. Patients with ongoing symptoms while on proton-pump inhibitor (PPI) therapy are commonly diagnosed with impedance–pH monitoring while continuing their medications. The impedance–pH monitoring diagnostic test determines the frequency of reflux episodes and the time relationship of reflux episodes and symptoms. The impedance–pH monitoring test determines if the patient's symptoms are related to