Question

4. Calculate the molarity of a solution of ethanol in water in which the mole fraction of ethanol is 0.040(density of water is 1g/cm3 ).

Answer 1

Dear Student,

Mole fraction of C2H5OH is 0.40
Density of water = 1
The moles of C2H5OH= X
The weight of 1000ml of water = volume * density (from density = mass/volume)
= 1000 x 1=1000g
Molecular mass of water is 18
The moles of water = 1000/18= 55.55 mol
Mole fraction of Ethanol = no. of moles of Ethanol / no. of moles of solution.
=>0.040 = X / X + 55.55
=>X =0.040X + 2.222
X= 2.3145 mol
Molarity of solutionof Ethanol is 2.314M.


Regards,