lets assume x volume of NaOH and x volume of HCl are added together. NaOH ---> Na⁺ + OH⁻ NaOH is a strong base therefore it completely ionizes and releases OH⁻ ions into the medium HCl ---> H⁺ + Cl⁻ HCl is a strong base and completely ionizes and releases H⁺ ions in to the medium. number of NaOH moles in 1 L - 0.1 mol Therefore in x L - 0.1 /1 * x = 0.1x moles of NaOH present Similarly in HCl x L contains - 0.1x moles of HCl H⁺ + OH⁻ ---> H₂O Due to complete ionisation, 0.1x moles of H⁺ ions and 0.1x moles of OH⁻ ions react to form 0.1x moles of H₂O. Therefore all H⁺ and OH⁻are completely used up and yield water molecules. Then at this point the H⁺ and OH⁻ ions in the medium come from the weak dissociation of water. This is equivalent to 1 x 10⁻⁷M pH = -log [H⁺] pH = -log [10⁻⁷] pH = 7 pH is therefore equals to 7 which means the solution is neutral
