Question

A 12.00 mL sample of acetic acid (CH₃COOH) is neutralized with 15.50 mL of 0.350 M Ca(OH)₂ in a titration. Find the concentration of the acetic acid.

a) 0.292 M
b) 0.427 M
c) 0.350 M
d) 0.215 M

Answer 1

To find the concentration of acetic acid, use the Henderson-Hasselbalch equation: [HA] = [A-] * 10^(pH - pKa).

Step-by-step explanation:

The volume of 12.00 mL of acetic acid neutralized by 15.50 mL of 0.350 M Ca(OH)₂ represents one-half of the stoichiometric amount of titrant. This means that one-half of the acetic acid has been neutralized. The concentrations of the acetic acid and the acetate ion formed will be equal. To find the concentration of the acetic acid, we can use the Henderson-Hasselbalch equation:

pH = pKa + log([A-]/[HA])

By rearranging the equation, we can solve for the concentration of the acetic acid:

[HA] = [A-] * 10^(pH - pKa)

Using the given values, we can substitute them into the equation to find the concentration of the acetic acid.