Question

During design of a chemical water treatment plant it is required to determine the amount of ferric chloride (FeCl3) to remove 40 Kg of sodium hydroxide (NaOH). Calculate the amount of FeCl3 in Kg. Governing equation is as follow: 

NaOH + FeCl3 → Fe(OH)3 + NaCl

Answer 1

According to the reaction three mole of the NaOH reacted with one mole of the ferric chloride. So to calculate the ammount of ferric chloride, first we have to calculate the moles of NaOH in 40 Kg. Moles can be calculated deviding weigh in gm by mol mass of that compound. After calculating the mole of NaOH we devided them by three as discussed above. The resulting moles will be the moles of Ferric chloride needed. Now calculate the weigh from mole by using mol. mass of ferric chloride. for calculation see attachment below.

by calculating 54 kg of ferric chloride is needed.