Calculate the mole fraction of ethylene glycol `(C_2H_6O_2)` in an aqueous solution containing 20% of `C_2H_4O_2` by mass.

Options

A. 0.68
B. 0.068
C. 0.932
D. 0.0932

Answer

B

Explanation

Weight of `C_2H_6O_2 = 20`
Molecular mass of `C_2H_4O_2 = 2 xx 12 + 6 + 16 xx 2 = 62`
Weight of water `= 100 - 20 = 80`
Mole fraction of `C_2H_6O_2= (20/62)/(20/62+ 80/18)= (0.322)/(0.322+4.44) = (0.322)/(4.77) =0.068`