Question

Calculate the molarity of a solution of ethanol in water in which the mole fraction of ethanol is .040(assume density of water to be one)

Answer 1

In such questions consider 10 moles of the solution in which 4 moles will be ethanol and 6 moles will be water. Since you know the number of moles of solute, all you need to find is volume of the solution. You have 6 moles of water, so calculate its weight(6 x 18 grams) and then calculate its volume(you know its density).