Answer:
Mole percent of water in azeotrope is 69%
Explanation:
Clearly, the azeotrope consists of water and perchloric acid.
So, 72% perchloric acid by mass means 100 g of azeotrope contains 72 g of perchloric acid and 28 g of water.
Molar mass of water = 18.02 g/mol and molar mass of perchloric acid = 100.46 g/mol
So, 72 g of perchloric acid = [tex]\frac{72}{100.46}mol[/tex] of perchloric acid = 0.72 mol of perchloric acid
Also, 28 g of water = [tex]\frac{28}{18.02}mol[/tex] of water = 1.6 mol of water
Hence total number of mol in azeotrope = (1.6+0.72) mol = 2.32 mol of azeotrope
So, mole percent of water in azeotrope = [(moles of water)/(total no of moles)][tex]\times 100[/tex]%
Mole percent of water = [tex]\frac{1.6}{2.32}\times 100[/tex] % = 69%
