Concept: The Graph 1 and 2 both represents the titration curve between strong acid and strong base, that is HCl (Hydrochloric acid) and NaOH (Sodium Hydroxide). Initially, the pH of NaOH is more than 7 but during the titration, it decreased. So, graph (1) is correct. In a strong acid-strong base titration, the acid and base will react to form a neutral solution. At the equivalence point of the reaction, hydronium (H+) and hydroxide (OH-) ions will react to form water, leading to a pH of 7. This is true for all strong acid and strong base titrations. The titration of hydrochloric acid (strong acid) and sodium hydroxide (strong base) to form sodium chloride and water. The reaction as follows, NaOH + HCl ⟶ NaCl + H2O In a weak base-strong acid titration, the acid and base will react to form an acidic solution. A conjugate acid will be produced during the titration, which then reacts with water to form hydronium ions. This results in a solution with a pH lower than 7. A strong acid is an acid that is completely dissociated or ionized in an aqueous solution. It is a chemical species with a high capacity to lose a proton H+. In water, a strong acid loses one proton, which is captured by water to form the hydronium ion. A strong base is a base that is completely dissociated in an aqueous solution. In contrast, a weak base only partially dissociates into its ions in water. Ammonia is a good example of a weak base. Strong bases react with strong acids to form stable compounds