A 1.00g sample of benzoic acid (C6H5CO2H, FW = 122.12g/mol,Ka = 6.5 x 10^ -5) is dissolved in water to give a solution with a volume of 500mL. What volume of 2.13M aqueous sodium benzoate (NaC6H5CO2) must be added to the aqueous benzoic acid solution to obtain a buffer with pH = 5.00?© BrainMass Inc. brainmass.com June 4, 2020, 3:47 am ad1c9bdddf
pH = pKa + log [sod.benzoate]/[benzoic acid]
[benzoic acid] = (1g/ 122.12g) x (1 mol / 0.500L) = ...
The method to calculate the amount needed to make a buffer at pH 5 is shown.