Question

Use the information below to answer the following question. What is the pH of a 0.100 M solution of benzoic acid?

Answer 1

Benzoic acid solutions are sometimes used in experiments to determine the molarity of a basic solution of unknown concentration.

Best Answer

PhCOOH(aq) --> PhCOO-(aq) + H+(aq)

Ka =[PhCOO-][H+]/[PhCOOH]

x = amount of acid dissociate, then [PhCOO-] = [H+] = x

Ka = x^2/( 0.1M - x ) = 0.000065

6.5 * 10 ^-6 - 6.5 * 10^-5x - x^2 = 0

solve for x = 0.00252 M

so pH = - log(0.00252) = 2.5 answer

Hope u understood well