1.29 Calculate the molarity of a solution of ethanol in water, in which the mole fraction of ethanol is 0.040 (assume the density of water to be one).

MolefractionofC2H5OH=NumberofmolesofC2H5OHNumberofmolesofsolution
0.040=nc2H5OHnc2H5OH+nH2O......i
Numberofmolespresentin1Lwater:
nH2O=1000g18gmol-1
nH2O=55.55mol
SubstitutingthevalueofnH2Oinequation1,
nc2H5OHnc2H5OH+55.55=0.040
nc2H5OH=0.040nc2H5OH+0.40455.55
0.96nc2H5OH=2.222mol
nc2H5OH=2.2220.96mol
nc2H5OH=2.314mol
Molarityofsolution=2.314mol1L
=2.314M