Certain salts of benzoic acid have been used as food additives for decades. The potassium salt of benzoic acid, potassium benzoate, can be made by the action of potassium permanganate on toluene.
C7H8 + 2 KMnO4 -------> KC7H5O2 + 2 MnO2 + KOH + H2O
toluene potassium
benzoate
If the yield of potassium benzoate cannot realistically be expected to be more than 68%, what is the minimum number of grams of toluene needed to achieve this yield while producing 10.0 g of KC7H5O2?