Substances such as Acetone (Propanone) are not normally expressed as a Molarity in the normal (concentrated) state as it is not dissolved in water. Instead, it should effectively be treated as a solid and the molecular weight used to make up molar solutions e.g. mol. wt. = 58.08 so weigh out 58g of solution and make up to 1 litre for a 1 molar solution. Use 116g made up to 1 litre for a 2 molar solution etc.