[srao]

The potassium salt of benzoic acid, potassium benzoate, KC7H5O2, can be made by the action of potassium permanganate on toluene, C7H8.
C7H8 + 2 KMnO4 --> 2MnO2 + KOH + H2O

If the yield of potassium benzoate cannot be realistically be expected to be more than 71%, what is the minimum number of grams of toluene needed to achieve this yield while producing 11.5 g of potassium benzoate?

please help ASAP.
thanks.

[Arkcon]

Your title indicates that you know you need to use the concept of moles to solve this problem.  But can you start with the definition?  You will need to convert grams to moles, then back again.