Answered

Find expert answers and community support for all your questions on IDNLearn.com. Ask anything and receive comprehensive, well-informed responses from our dedicated team of experts.

A sample of acetic acid is titrated with a standardized NaOH solution. Beyond the end-point of the titration, which of the following must be true?

[tex]\[ HC_2H_3O_2(aq) + NaOH(aq) \longrightarrow NaC_2H_3O_2(aq) + H_2O(l) \][/tex]

Note: [tex]\([X] =\)[/tex] molar concentration of [tex]\(X\)[/tex]

A. [tex]\(\left[ H^+ \right] \ \textless \ [ OH^- ]\)[/tex]

B. [tex]\(\left[ H^+ \right] \ \textgreater \ [ OH^- ]\)[/tex]

C. [tex]\(\left[ H^+ \right] = [ OH^- ]\)[/tex]

Sagot :

GinnyAnsweridn
To understand what happens beyond the end-point of a titration involving acetic acid ([tex]\(HC_2H_3O_2\)[/tex]) and sodium hydroxide ([tex]\(NaOH\)[/tex]), we should consider the stoichiometry and the nature of the substances involved.

Let's analyze the titration process step-by-step:

1. Equation and Reaction:
The balanced chemical equation is:
[tex]\[ HC_2H_3O_2(aq) + NaOH(aq) \longrightarrow NaC_2H_3O_2(aq) + H_2O(l) \][/tex]
Here, acetic acid ([tex]\(HC_2H_3O_2\)[/tex]) reacts with sodium hydroxide ([tex]\(NaOH\)[/tex]) to produce sodium acetate ([tex]\(NaC_2H_3O_2\)[/tex]) and water ([tex]\( H_2O\)[/tex]).

2. Titration End-Point:
The end-point of the titration is reached when the amount of [tex]\(NaOH\)[/tex] added is stoichiometrically equivalent to the amount of [tex]\(HC_2H_3O_2\)[/tex] present. At this point, all of the [tex]\(HC_2H_3O_2\)[/tex] has been neutralized by [tex]\(NaOH\)[/tex], and the solution contains [tex]\(NaC_2H_3O_2\)[/tex] (which is a salt of the weak acid [tex]\(HC_2H_3O_2\)[/tex]) and water.

3. Beyond the End-Point:
Beyond the end-point, excess [tex]\(NaOH\)[/tex] has been added to the solution. This means there is a surplus of [tex]\(OH^-\)[/tex] ions because [tex]\(NaOH\)[/tex] dissociates completely in water:
[tex]\[ NaOH(aq) \rightarrow Na^+ (aq) + OH^- (aq) \][/tex]

4. pH Consideration:
As [tex]\(NaOH\)[/tex] is a strong base and it dissociates completely, the excess [tex]\(OH^-\)[/tex] ions will increase the alkalinity of the solution. In other words, beyond the end-point, the concentration of [tex]\(OH^-\)[/tex] ions will be greater than the concentration of [tex]\(H^+\)[/tex] ions, leading to a basic or alkaline solution.

Given these points, beyond the end-point of titration, the correct statement about the relative concentrations of hydrogen ions ([tex]\(H^+\)[/tex]) and hydroxide ions ([tex]\(OH^-\)[/tex]) is:

[tex]\[ \left[ H ^{+}\right] < [ OH^- ] \][/tex]

This means the solution is basic beyond the end-point because there are more hydroxide ions than hydrogen ions present.
We appreciate your contributions to this forum. Don't forget to check back for the latest answers. Keep asking, answering, and sharing useful information. Thank you for visiting IDNLearn.com. We’re here to provide dependable answers, so visit us again soon.