SEPERATION TECHNIQUES

When the boiling temperature is plotted against the liquid composition, then it is called

• Cooling Curve

• Heating Curve

• Bubble point curve

• Volatility Phase Diagram

Answer explanation

The (T-x) curve is called as Bubble point Curve, Where T is boiling temperature and x is the mole fraction of the liquid.

When the temperature is plotted against the equilibrium vapor, then it is called

• Condensing Curve

• Dew Point curve

• Equilibrium Curve

• Bubble Curve

Answer explanation

The (T-y*) curve is called as Dew point Curve, Where T is boiling temperature, and y is the equilibrium moles of the gaseous components.

Which of the following shows the correct Gibbs phase rule equation?

• F=C-P+2

• P=C+P

• C=F-P+2

• C=P-F

Answer explanation

According to Gibb’s F=C-P+2 for any system, where F is degree of freedom, C is number of components and P is the number of phases.

The higher the concentration of volatile species, the distillation

• The higher the rate of liquid flow

• The lower the rate of Separation

• The higher the rate of separation

• Cannot be specified

Answer explanation

Volatility is directly proportional to the ease of separation (α) while it is inversely proportional to difficulty of separation.

Which of the following statements regarding Ideal solutions is false?

• Ideal solutions obey Raoult’s law under all conditions of temperature and concentrations
  

• There will be some change in volume on mixing the components, i.e., ΔV_mixing ≠ 0

• There will be no change in enthalpy when the two components are mixed, i.e., ΔH_mixing = 0

• There will be no change in volume on mixing the components, i.e., ΔV_mixing = 0

Answer explanation

An ideal solution is the solution in which each component obeys Raoult’s law under all conditions of temperature and concentrations. An ideal solution will satisfy the following conditions:
I. There will be no change in volume on mixing the components, i.e., ΔV_mixing = 0.
II. There will be no change in enthalpy (i.e., no heat is evolved or absorbed) when the two components are mixed, i.e., ΔH_mixing = 0.

According to Raoult's law the partial vapour pressure of each component in the solution is directly proportional to its

• Volume

• Mole fraction

• Molality

• Density

Answer explanation

Raoults law states that the partial vapour pressure of each component in the solution is directly proportional to its mole fraction.

What is the dew point equation?

• ∑ yiki=0

• ∑ yi/ki=0

• ∑ yiki=1

• ∑ yi/ki=1

Answer explanation

Equilibrium relationship

What is true about vapor- liquid equilibrium?

• Vapor is at its dew point and liquid at its bubble point

• Vapor at its bubble point and liquid at its dew point

• Both the liquid and vapor at dew point

• Both the liquid and vapor at bubble point

Which of the following is true regarding azeotropes?

• An azeotrope does not exhibit the same concentration in the vapour phase and the liquid phase
  
  

• Azeotropic mixtures cannot be separated into their constituents by fractional distillation

• In case of minimum boiling azeotropes, the boiling point of the azeotrope is higher than the boiling point of either of the pure components

• In case of maximum boiling azeotropes, the boiling point of the azeotrope is lesser than the boiling point of either of the pure components

Answer explanation

Azeotropes have the same concentration in the vapour phase and the liquid phase. In case of minimum boiling azeotropes, the boiling point of the azeotrope is lesser than the boiling point of either of the pure components. In case of maximum boiling azeotropes, the boiling point of the azeotrope is higher than the boiling point of either of the pure components.

What is the bubble point equation?

• ∑ xiki=0

• ∑ xi/ki=0

• ∑ xiki=1

• ∑ xi/ki=1

Answer explanation

Equilibrium relationship