CHEM101: General Chemistry I

Water acts as a base when reacted with a strong acid. This seems odd, since we know water is neutral. Water is an amphiprotic compound, meaning it can act as either an acid or a base. When an acid reacts with water, the water will act as a base. When a base reacts with water, the water will act as an acid. Water also autoionizes, meaning it can form H+ and OH-. This video shows how two water molecules react to form hydronium ion (H₃O⁺, an acid), and OH^-, but is still overall pH-neutral.