Benzoic acid,

CHEMISTRY · Multi-part · AP · Chemistry · Acids and Bases · Acids and Bases

Problem

Benzoic acid,

\text{C}_6\text{H}_5\text{COOH}

, is a weak monoprotic acid. A

25.0\,\text{mL}

sample of

0.100\,\text{M}

benzoic acid is allowed to reach equilibrium at

25\,\text{°C}

, after which the pH of the solution is measured to be 2.65. (a) Calculate the percent ionization of benzoic acid under the given conditions. (b) Use the information provided to determine the numerical value of

K_a

for benzoic acid. The literature value at

25\,\text{°C}

K_a = 6.3\times10^{-5}

. Calculate the percent error between your experimental value and the literature value. (c) The equilibrium mixture from part (a) is quantitatively transferred to a volumetric flask and diluted to a total volume of

250\,\text{mL}

with deionized water at

25\,\text{°C}

. Assuming

K_a

remains constant, predict the new percent ionization and the pH of the diluted solution. Show all reasoning and calculations.

Related theory

Browse the problem library