Aliquid mixture containing 30 wt% acetone (a) and 70 wt% water (w) is fed to a distillation column operating at steady-state. a top product stream contains 90 wt% a while the bottom product stream contains 5% of the a fed to the column and the rest with. your rotameter indicates you are pumping 100 l/h of the mixture into the column. the specific gravity of the feed is 0.75. how many independent material balances can be written?