Multiple Choice
Use the titration curve below.
What is the predominate species in the solution of phosphoric acid at pH = 5?
2. Water
Titration
Struggling with Biochemistry?
Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
You have an analyte solution of 50 mL of 0.2 M acetic acid (pKa = 4.8). What volume of 0.05 M NaOH titrant needs to be added to get the final pH = pKa?
A
20 mL
B
50 mL
C
100 mL
D
150 mL
Verified step by step guidance1
Understand that the problem involves a titration of acetic acid with NaOH, and the goal is to reach a pH equal to the pKa of acetic acid, which is 4.8.
Recall that when the pH of a solution equals the pKa of the acid, the concentrations of the acid and its conjugate base are equal. This is the half-equivalence point in a titration.
Calculate the initial moles of acetic acid in the solution using the formula: moles = concentration (M) × volume (L). For 50 mL of 0.2 M acetic acid, convert the volume to liters and multiply by the concentration.
At the half-equivalence point, half of the acetic acid will have been converted to its conjugate base, acetate. Therefore, the moles of NaOH added will equal half the initial moles of acetic acid.
Determine the volume of 0.05 M NaOH needed to provide the calculated moles of NaOH. Use the formula: volume (L) = moles / concentration (M), and convert the volume to milliliters.
Related Videos
Related Practice
