Which of the following is NOT a form of alkalinity?

The correct answer identifies hypochlorite as not being a form of alkalinity. Alkalinity in water refers to the capacity of water to neutralize acids, and it primarily arises from certain ions that can react with hydrogen ions (H+). Common forms of alkalinity include bicarbonate, hydroxide, and carbonate, all of which contribute to the buffering capacity of water.

Bicarbonate ions can consume hydrogen ions, therefore increasing the alkalinity. Hydroxide ions also raise the pH by providing a basic condition in water. Carbonate ions further increase the alkalinity through similar reactions.

In contrast, hypochlorite is a chemical compound commonly used as a disinfectant and bleaching agent, which does not directly participate in the same alkalinity reactions as the other ions. It does not serve to neutralize acids in the same manner and is not classified as a contributor to alkalinity in water chemistry. This distinction makes hypochlorite the option that does not align with the definition of forms of alkalinity.