Question

A mixture of air and benzene is found to have a relative saturation of 50% at a temperature of 27 °C and an absolute pressure of 110 kPa. What is the mole fraction of benzene in air?

Answer 1

To find the mole fraction of benzene in air, apply Dalton's law of partial pressures. First, calculate the partial pressure of benzene using the relative saturation. Then, use the formula for mole fraction to determine the fraction of benzene in air.

Step-by-step explanation:

To find the mole fraction of benzene in air, we can use Dalton's law of partial pressures.

Dalton's law states that the total pressure of a mixture of gases is equal to the sum of the partial pressures of each gas.

In this case, we know the relative saturation of the mixture is 50% and the absolute pressure is 110 kPa.

Since the relative saturation is the ratio of the partial pressure of benzene to the total pressure, we can set up the equation:

0.5 = P_benzene / 110 kPa

Solving for P_benzene:

P_benzene = 0.5 * 110 kPa = 55 kPa

The mole fraction of benzene in air can be calculated using the formula:

X_benzene = P_benzene / P_total

Substituting the values:

X_benzene = 55 kPa / 110 kPa = 0.5

Therefore, the mole fraction of benzene in air is 0.5.

Answer 2

0.67

Step-by-step explanation:

The vapour pressure of pure benzene and toluene at a particular temperature are

100

m

m

and

50

m

m

respectively. Then the mole fraction of benzene in vapour phase in contact with equimolar solution of benzene and toluene is :