Which of the following is a common pH increasing chemical?

Soda Ash, also known as sodium carbonate, is commonly used to increase pH levels in water. It is particularly effective in water treatment processes, where maintaining a specific pH range is crucial for various operational reasons, such as corrosion control, disinfection efficacy, and chemical stability. When soda ash is added to water, it reacts to release carbonate ions, which raise the pH by neutralizing acids present in the water. This is essential for processes that require alkaline conditions.

In contrast, the other chemicals listed serve different purposes. Sodium nitrate is primarily used as a fertilizer and does not have a significant effect on pH levels. Calcium chloride is usually employed for coagulation and can actually lower pH, while sodium bicarbonate, while it can raise pH, is generally used to maintain or buffer pH rather than increase it as effectively as soda ash. Thus, soda ash is recognized for its specific role in effectively increasing pH levels in water treatment applications.