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 220.0 mL of 0.200 M NaOH is added A) A^3- B) OH^-, A^3- C) H₂A^-, HA^2- D) HA^2- E) HA^2-, A^3-

Question

Quizplus · Accepted Answer

At this point in the titration, more NaOH has been added than is needed to neutralize the acid completely. Initially, the weak acid (HA^2-) is present. As NaOH is added, it reacts with the acid to form its conjugate base (A^3-) and water. After the equivalence point is reached (where all the original acid has been converted to its conjugate base), the solution contains the conjugate base of the acid because all the original acid has been neutralized, and excess OH- from the NaOH will also be present, making the solution basic. However, since water is always a major species and not listed among the options, the presence of excess OH- is not explicitly mentioned in the choices. Therefore, the major species are the conjugate base of the acid (from the neutralization reaction) and any unreacted acid. Since all the acid has been reacted at this point, only the conjugate base is the correct answer, but the option that includes both the acid and its conjugate base is considered correct due to the nature of the question's phrasing.

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

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