Titration Curves Quiz

The graph opposite shows the titration curve for an aqueous solution of a weak base, B, with HCl as the titrant. Based on the graph, which of the following best estimates the pKB of HB+?

• 12.0

• 10.8

• 6.0

• 1.8

The reaction of a weak base, B, with HCl is represented by the equation above. The graph (Q1) shows the titration curve for 25.0mL of an aqueous solution of B titrated with 0.100MHCl. Based on the graph, which of the following best estimates the initial concentration of the solution of the weak base?

• 0.20 M

• 0.10 M

• 0.067M

• 0.048 M

A 40.0mL sample of the weak base C5H11N was titrated with 1.00 M HCl at 25°C. Based on the resulting titration curve shown opposite, which of the following pairs provide the best estimates for the pKB and KB of C5H11N?

• pKB = 3.0 and KB = 1x 10^-3

• pKB = 5.8 and KB = 2 x 10^-6

• pKB = 11.0 and KB = 1x 10^-11

• pKB = 12.5 and KB = 3x 10^-2

A solution of a weak monoprotic acid is titrated with a solution of a strong base, KOH. For Q 4-6 that follow, choose from the points labeled (A) through (E) on the titration curve. The point at which the concentrations of the weak acid and its conjugate base are approximately equal.

• A

• B

• C

• D

• E

A solution of a weak monoprotic acid is titrated with a solution of a strong base, KOH. For Q 4-6 that follow, choose from the points labeled (A) through (E) on the titration curve. The point at which the moles of the added strong base are equal to the moles of the weak acid initially present.

• A

• B

• C

• D

• E

A solution of a weak monoprotic acid is titrated with a solution of a strong base, KOH. For Q 4-6 that follow, choose from the points labeled (A) through (E) on the titration curve. The point at which the pH is closest to that of the strong base being added.

• A

• B

• C

• D

• E

Data collected during the titration of a 20.0 mL sample of a 0.10 M solution of a monoprotic acid with a solution of NaOH of unknown concentration are plotted in the graph opposite. Based on the data, which of the following are the approximate pKa of the acid and the molar concentration of the NaOH?

• pKa = 4.7 and [NaOH] = 0.050 M

• pKa = 4.7 and [NaOH] = 0.10 M

• pKa = 9.3 and [NaOH] = 0.050 M

• pKa = 9.3 and [NaOH] = 0.10 M

At point R in the titration, which of the following species has the highest concentration?

• HA

• A^-

• H_3O^+

• OH^-

A student carries out the same titration, but uses an indicator instead of a pH meter. If the indicator changes color slightly past the equivalence point, what will the student obtain for the calculated concentration of the acid?

• Slightly less than 0.0800 M

• Slightly more than 0.0800 M

• Slightly less than 0.125 M

• Slightly more than 0.125 M

Which of the following is the best particulate representation of the species (other than H_2O) that are present in significant concentrations in the solution at point U in the titration?

• Diagram A

• Diagram B

• Diagram C

• Diagram D