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).
Given that the mole fraction of ethanol in water is .
To find the molarity we must have to find the number of moles of ethanol present in 1litre of solution.
Assuming the density of water to be .
Therefore, water is approximately equal to 1Litre.
The number of moles in 1L of water:
So, substituting in place of in above equation we get,
So, are present in 1L of solution.
Hence, the molarity of the solution is