Consider the titration of an acetic acid solution with a sodium hydroxide soluti

Question

Consider the titration of an acetic acid solution with a sodium hydroxide solution at the following three stages of the titration: (i) before the titration begins, (ii) when the number of moles of sodium hydroxide added is equal to 1/2 the number of moles of acetic acid originally in the beaker, and (ii) at the endpoint. For each of the following questions, select one of the above three stages and explain your reasoning. a. When does the reaction solution contain mostly acetate ion? b. When does it contain mostly acetic acid? c. When does it contain significant amounts of both? d. At what point during the titration is the reaction solution's pH at its lowest value? e. At what point is the pH at its highest value?

Explanation / Answer

a. (iii) at the endpoint.

Here we have completely neutralised acetic acid with NaOH. So we have salt solution of sodium acetate. Salt will ionize to provide acetate ions.

b. (i) before the titration begins

Initially we only have acetic acid and no NaOH is added.

c. (ii) When the number of moles of NaOH added is equal to one half the number of moles of acetic acid originally in the beaker. This corresponds to half equivalence point. The added NaOH have neutralised one half of the acetic acid. Thus, equal amounts of acetic acid and acetate ions are present.

d. (i) before the titration begins

Lowest pH means most acidic solution.

Initially we only have acetic acid and no NaOH is added.

e. (iii) at the endpoint.

Maximum pH means least acidic (or most basic) solution.

Here we have completely neutralised acetic acid with NaOH. So we have salt solution of sodium acetate. It is salt of weak acid with strong base. Such solutions are basic in nature.

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.