[Campbell Biology P.101] According to the text, if 0.01 mol of a strong acid is added to a l... | Practice Question

According to the text, if 0.01 mol of a strong acid is added to a liter of pure water, the pH drops from 7.0 to 2.0. However, if the same amount of acid is added to a liter of human blood, the pH only drops from 7.4 to 7.3. What is the primary reason for this difference in pH change?

  • A: Human blood is naturally more acidic than pure water.
  • B: Human blood contains buffers that resist changes in pH.
  • C: Pure water has a higher initial pH than human blood.
  • D: The acid reacts differently with the components of water versus blood.

Explanation

The text explains that 'A buffer is a substance that minimizes changes in the concentrations of H+ and OH- in a solution.' Human blood contains such buffer systems, which are responsible for maintaining its stable pH despite the addition of acids or bases.