Which chemical is commonly used for pH adjustment?

• A. Hydrochloric acid
• B. Sodium Bicarbonate
• C. Sodium Hydroxide
• D. Calcium Carbonate

Answer: (C)

The use of sodium hydroxide for pH adjustment is prevalent due to its strong alkaline properties, making it effective in raising the pH of wastewater. When added to an acidic solution, sodium hydroxide reacts with the acids to neutralize them and increase the pH level. This capability is crucial in wastewater treatment processes, where maintaining appropriate pH levels ensures optimal conditions for biological treatment and reduces corrosion in pipes and equipment.

Sodium hydroxide dissociates completely in water, providing a more immediate and powerful change in pH compared to some other options. This feature is particularly important in industrial applications where rapid pH adjustment is required. Other chemicals like hydrochloric acid can lower pH, while sodium bicarbonate and calcium carbonate are milder agents that might be used for buffering rather than direct adjustment, making sodium hydroxide the preferred choice for significant increases in pH.