Question

What is the approximate molar fraction of ethanol c2h5oh in an aqueous solution in which the ethanol concentration is 11.0 molal?
A. 0.0011
B. 0.011
C. 0.170
D. 0.200
E. 0.600

Answer 1

I assume you mean mole fraction, XC2H5OH.

11 m means 11 mols C2H5OH/kg solvent or
11 mols/(11 mol C2H5OH + 1000 gH2O)
Convert 1000 g H2O to mols = about 55 but you need to do it more accurately.
Total mols = 11 + 55 = about 66
XC2H5OH = (11/66) = about 0.167.