Question

In a storage tank, a mixture liquid containing 50mol% methanol and the rest ethanol is kept at 50^oC.Assuming no other compound is present in the tank.Determine the composition of the gas phase if some parts of the liquid mixture evaporate to a vapor phase using Raoult's law.

Answer 1

From Antoine's equation, we have

For methanol at temperature = 50⁰C

For ethanol at temperature = 50⁰C

Now,

Using Roult's law, partial pressure for methanol at 50⁰C

is the vapor pressure of methanol as calculated by antoine's equation above

Now, we can write

So, mole fraction of methanol in vapor phase is 0.273762

Now,

Using Roult's law, partial pressure for ethanol at 50⁰C

is the vapor pressure of ethanol as calculated by antoine's equation above

Now, we can write

So, mole fraction of ethanol in vapor phase is 0.14492