Which of the following is NOT a form of alkalinity?

Hypochlorite is not considered a form of alkalinity. Alkalinity refers to the capacity of water to resist changes in pH and is primarily associated with the presence of certain ions that can neutralize acids. The main contributors to alkalinity are bicarbonate, carbonate, and hydroxide ions.

Bicarbonate and carbonate are crucial components of the carbonate buffering system and play a significant role in maintaining the pH of natural waters. Hydroxide ions contribute to alkalinity as they can neutralize acids, adding to the water's buffering capacity.

In contrast, hypochlorite, which is often found in disinfectants and bleach, does not contribute to alkalinity in the same way. It does not provide a buffering action against acids and is primarily used for its oxidation properties rather than for its ability to neutralize acidic conditions in water. This makes hypochlorite distinct from the other options that are integral to defining alkalinity in water chemistry.