Question

At 80 degrees celsius the vapor pressure of benzene is 753 torr and that of toluene is 290 torr. What is the total pressure and what is the composition of the vapor of a solution that is 2/3 benzene and 1/3 toluene?

Answer 1

Answer:

The total pressure of the solution is 598.66 torr

while the vapor pressure of the components is vapor pressure of benzene is =502 torr and that of toluene = 96.6 tor

Explanation:

To solve this question, we need to look at the known variables, the unknown variables, and then we select the appropriate relations between the known variables and the unknown

Here we have the temperature of the gases t = 80°C

the pressures of benzene = 753 torr

the pressures of toluene = 290 torr

mole fraction of benzene in solution = 2/3

mole fraction of toluene in solution = 1/3

the unknown variables = composition of the solution  and the total pressure of the solution

From here given the known variables and the required variables, the appropriate relation bstween the known and unknown variables is Route's Law

Raoult's relates the vapor pressure of a mixture of gases to the mole fraction of solute gases introduced in the  gas solution. Raoult's Law is expressed by the formula: Psolution = Χsolvent1×Psolvent1 + Χsolvent2×Psolvent2+ ... .

where. Psolution = vapor pressure of the solution and

Χsolvent1 = mole fraction of solvent 1

Psolvent1 = vapor pressure of solvent1

Thus we have by Raoult's Law

$P_{solution}$ = $X_{benzene}$ × $P_{benzene}$+ $X_{toluene}$×$P_{toluene}$

which is =2/3×753 + 1/3×290 = 502 + 96.6 = 598.66 torr

and composition vapor pressure of benzene is 502 torr

while the composition vapor pressure of toluene is 96.6 torr