A reasonably general expression for vapour-liquid phase equilibrium at low to moderate pressure is φi yi P = Yi xifi° where, Φ is a vapor fugacity component, Yi is the liquid activity coefficient and fi° is the fugacity of the pure component i. the Ki value (Yi = Ki xi) is therefore, in general a function of ______________________?

Related Mcqs:

1. Fugacity of a component in an ideal gas mixture is equal to the partial pressure of that component in the mixture. The fugacity of each component in a stable homogeneous solution at constant pressure and temperature ____________ as its mole fraction increases?

   A. Decreases
   B. Decreases exponentially
   C. Increases
   D. Remain constant

2. “The fugacity of a gas in a mixture is equal to the product of its mole fraction and its fugacity in the pure state at the total pressure of the mixture”. This is__________________?

   A. The statement as per Gibbs-Helmholtz
   B. Called Lewis-Randall rule
   C. Henry’s law
   D. None of these

3. The ratio of existing moles of vapor per mole of vapor free gas to the moles of vapor that would be present per mole of vapor free gas, if the mixture were saturated at the existing temperature & pressure, is termed as the_____________________?

   A. Relative humidity
   B. Relative saturation
   C. Percentage saturation
   D. None of these

4. Free energy, fugacity and activity co-efficient are all affected by change in the temperature. The fugacity co-efficient of a gas at constant pressure ______________ with the increase of reduced temperature?

   A. Decreases
   B. Increases
   C. Remains constant
   D. Decreases logarithmically

5. For water at 300°C, it has a vapour pressure 8592.7 kPa and fugacity 6738.9 kPa Under these conditions, one mole of water in liquid phase has a volume of 25.28 cm3 and that in vapour phase in 391.1 cm3.Fugacity of water (in kPa) at 9000 kPa will be__________________?

   A. 6738.9
   B. 6753.5
   C. 7058.3
   D. 9000

6. Assuming applicability of ideal gas law, the pure component volume of the vapor in a saturated gas can be calculated from theoretical relationship. The volumetric composition of a vapor saturated gas is independent of the___________________?

   A. Nature of the liquid
   B. Nature of the gas
   C. Temperature of the liquid
   D. Total pressure

7. The percentage ratio of the partial pressure of the vapor to the vapor pressure of the liquid at the existing temperature is_____________________?

   A. Termed as relative saturation
   B. Not a function of the composition of gas mixture
   C. Called percentage saturation
   D. Not a function of the nature of vapor

8. Fugacity co-efficient of a substance is the ratio of its fugacity to__________________?

   A. Mole fraction
   B. Activity
   C. Pressure
   D. Activity co-efficient

9. According to Raoult’s law, “The vapor pressure exerted by component in a solution is proportional to the mole fraction of that component.” Raoult’s law is not applicable under the following assumption/condition?

   A. No component is concentrated at the surface of the solution
   B. The component molecules are non polar and are of almost equal size
   C. In the formation of solution, chemical combination/molecular association between unlike
   molecules takes place
   D. The attractive forces between like and unlike molecules are almost equal

10. If the partial pressure of the solvent in the vapor phase is equal to the vapor pressure of the solvent at that temperature, then the system is said to be at its___________________?

    A. Bubble point
    B. Saturation temperature
    C. Dew point
    D. Both B. and C.