A 200.0-mL sample of the weak acid H 3 A (0.100 M) is titrated with 0.200 M NaOH. What are the major species at each of the following points in the titration? (Water is always assumed to be a major species.) -After 75.0 mL of 0.200 M NaOH is added A) H₂A^- B) HA^2- C) H₃A, H₂A^- D) H₂A^-, HA^2- E) H₃A

Question

Quizplus · Accepted Answer

At the equivalence point, all of the acid (H₃A) will have reacted with the base (NaOH) and the resulting solution will consist of the conjugate base (H₂A^-) and the excess base (NaOH). However, we are not yet at the equivalence point, so some of the acid has been neutralized but we still have both acid and base present. At the halfway point (75.0 mL of 0.200 M NaOH), we have added half of the amount of NaOH needed to reach the equivalence point. This means that half of the acid has been neutralized, leaving a mixture of the weak acid (H₃A) and its conjugate base (H₂A^-) in solution. Therefore, the best choice is C.

A 2000-ML Sample of the Weak Acid H3A (0

A 2000-ML Sample of the Weak Acid H₃A (0