Which chemical buffers excessive acetoacetic acid?

• A. Potassium
• B. Sodium bicarbonate
• C. Carbon dioxide
• D. Sodium chloride

Answer: (B)

The main idea is how the body's buffering system neutralizes excess acid. When acetoacetic acid builds up, the bicarbonate buffering system steps in. Bicarbonate ions react with the hydrogen ions from the acid to form carbonic acid, which then rapidly becomes CO2 and water. The CO2 is exhaled, helping prevent a drop in pH. Among the options, sodium bicarbonate provides the bicarbonate ion needed to absorb the extra H+, making it the correct buffer. Potassium and sodium chloride are just salts/electrolytes and don’t neutralize added acid, while carbon dioxide is a product of the buffering reaction, not the buffering agent itself.