Sodium benzoate is considered one of the most commonly used preservatives
in the pharmaceutical industry. How
much sodium benzoate, Ka = 6.4 X10-
5, will remain undissociated in the
aqueous phase of a 25% oil-water
emulsion if the initial amount of sodium
benzoate in the aqueous phase is 0.5
mole? The pH of the used 100 ml of the
aqueous phase was buffered at pH 5
and the o/w partition coefficient = 5.33.
Assume that sodium benzoate remains
as a monomer in the oil phase.
Select one:
a. 7.86* 10-3 g/ml
b. 0.031 g/100ml
C. 0.0786 g/100 ml​