(a) How much of the primary standard benzoic acid (FM 122.12, density = 1.27 g/mL) should you weigh out to obtain a 100.0 mM aqueous solution in a volume of 250 mL? 

(b) What apparent mass in air will give you the true mass in (a)?

(c) Serial dilution. You have available 5- and 10-mL transfer pipets plus volumetric flasks of the following sizes: 100, 250, 500, and 1 000 mL. Devise a serial dilution that will give 50.0 mM benzoic acid.