Question 1

Which titration curve best represents the titration of a strong acid with a strong base?

Accepted Answer

The second image, where the pH starts low and rises sharply at the equivalence point.

Question 2

In the first titration curve, what is the pH at the half-equivalence point, and what does this value represent?

Accepted Answer

pH = 9.25; it equals the pKa of the conjugate acid of the weak base.

Question 3

Which of the following statements is TRUE regarding the equivalence point in the titration of a weak base with a strong acid (as shown in the first image)?

Accepted Answer

The pH at the equivalence point is less than 7 because the conjugate acid of the weak base hydrolyzes to produce H$$_3O$^+.$$

Question 4

For the titration curve in the third image, which of the following best describes the solution at the equivalence point?

Accepted Answer

The solution contains only the conjugate base of the weak acid and water.

Question 5

Given the titration of 0.10 M NH$$_3$$ with HCl (first image), what is the major species present at the equivalence point?

Accepted Answer

NH$$_4^+$$

Question 6

Which titration curve would you expect if you titrate a weak acid with a strong base?

Accepted Answer

The third image, where the pH starts low and rises above 7 at the equivalence point.

Question 7

If you add a few drops of phenolphthalein (pH transition range 8.2–10.0) to the solution in the second titration curve, at what point will the indicator change color?

Accepted Answer

Just after the equivalence point, as the pH rises above 8.2.

Question 8

In the first titration curve, what is the buffer region and what is its significance?

Accepted Answer

The buffer region is the relatively flat portion before the equivalence point, where the solution resists changes in pH upon addition of acid or base.

Question 9

Which equation would you use to calculate the pH at the half-equivalence point in the titration of a weak base with a strong acid?

Accepted Answer

$$\$$\mathrm{pH} = \mathrm{p}K_\mathrm{a}$$ of the conjugate acid of the base\$$\$

Question 10

In the second titration curve, what is the main reason for the sharp increase in pH near the equivalence point?

Accepted Answer

The rapid neutralization of the strong acid by the strong base, resulting in a small excess of base causing a large pH change.

Question 11

For the titration curve in the first image, which equation would you use to calculate the pH after adding a known volume of strong acid to the weak base?

Accepted Answer

$$\$$\mathrm{pH} = \mathrm{p}K_\mathrm{a} + \log \left( \frac{[	ext{base}]}{[	ext{acid}]} ight)\$$\$$

Question 12

Which titration curve would you expect if you titrate a strong base with a strong acid?

Accepted Answer

The second image, where the pH starts high and drops to 7 at the equivalence point.

Question 13

In the third titration curve, what is the likely identity of the acid being titrated?

Accepted Answer

A weak acid, because the initial pH is above 2 and the equivalence point is above pH 7.

Question 14

If you titrate 50.0 mL of 0.10 M acetic acid (weak acid) with 0.10 M NaOH, which titration curve would you expect?

Accepted Answer

The third image, where the pH starts low and rises above 7 at the equivalence point.

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