Which term describes a solution that resists pH changes?

Which term describes a solution that resists pH changes?

• A. Biomass
• B. Buffer
• C. Biosolids
• D. BOD

Answer: (B)

A solution that resists pH changes is called a buffer. A buffer contains a weak acid and its conjugate base (or a weak base and its conjugate acid) that neutralize small amounts of added acid or base, keeping the pH stable. If an acid is added, the buffer’s conjugate base consumes the extra H+ ions, forming the weak acid. If a base is added, the buffer’s weak acid neutralizes the OH− ions, forming more of the conjugate base. In wastewater treatment, buffering is provided mainly by carbonate alkalinity (bicarbonate and carbonate species), which helps maintain pH during processes that generate or consume acidity. This pH stability supports microbial activity and chemical treatment steps. Other terms describe different things—biomass, biosolids, or BOD—and do not describe a substance that resists pH changes.

A solution that resists pH changes is called a buffer. A buffer contains a weak acid and its conjugate base (or a weak base and its conjugate acid) that neutralize small amounts of added acid or base, keeping the pH stable. If an acid is added, the buffer’s conjugate base consumes the extra H+ ions, forming the weak acid. If a base is added, the buffer’s weak acid neutralizes the OH− ions, forming more of the conjugate base. In wastewater treatment, buffering is provided mainly by carbonate alkalinity (bicarbonate and carbonate species), which helps maintain pH during processes that generate or consume acidity. This pH stability supports microbial activity and chemical treatment steps. Other terms describe different things—biomass, biosolids, or BOD—and do not describe a substance that resists pH changes.