Which of the following assumes constant molal vaporisation and
overflow?
(A) McCabe-Thiele method
(B) Ponchan-Savarit method
(C) Enthalpy concentration method
(D) Plate absorption column
Description : In distillation column design, the McCabe-Thiele procedure is inadequate and a Ponchan-Savarit procedure is needed, when (A) Saturated feed is not used (B) An azeotrope forms (C) The latent ... vaporisation of the more and less volatile components are greatly different (D) A total condenser is used
Last Answer : (D) A total condenser is used
Description : Pick out the correct statement. (A) Ponchan-Savarit method is more accurate than McCabe-Thiele method to determine the number of theoretical stages required for the separation of ... Flash distillation is suitable for separating components which have very close boiling temperature
Last Answer : (A) Ponchan-Savarit method is more accurate than McCabe-Thiele method to determine the number of theoretical stages required for the separation of nonideal binary system by distillation
Description : Design calculation for multiple component distillation is done by (A) Ponchon-Savarit method (B) McCabe-Thiele method (C) Enthalpy concentration method (D) Tray to tray calculations
Last Answer : (D) Tray to tray calculations
Description : McCabe-Thiele method (A) Uses molal units for material and energy balance (B) Uses weight fractions to express liquid and vapour composition (C) Can use any type of units (D) Is more accurate than Ponchon-Savarit method
Last Answer : (A) Uses molal units for material and energy balance
Description : Ponchon-Savarit method analyses the fractional equipment based on (A) Enthalpy balance only (B) Material balance only (C) Both enthalpy and material balances (D) The assumption of constant molal-overflow
Last Answer : (C) Both enthalpy and material balances
Description : Pick out the wrong statement. (A) Different solids have different equilibrium moisture curves (B) Total condenser or reboiler is considered equivalent to one theoretical plate in McCabe-Thiele method of ... (D) Even a forced draft cooling tower cannot cool water below the wet bulb temperature
Last Answer : (C) Heat removal load on cooler remains constant, even with increase of the reflux ratio in a distillation column
Description : In McCabe-Thiele method of theoretical plate calculation for a distillation column, the operating lines of stripping and rectifying sections coincide with the diagonal at __________ reflux. (A) Total (B) Minimum (C) Operating (D) Maximum permissible
Last Answer : (A) Total
Description : Pick out the wrong statement. (A) In the McCabe-Thiele diagram for binary distillation, vertical feed line represents saturated liquid feed and horizontal feed line represents saturated vapour feed (B) In ... layers over a flat plate are of equal thickness, if Schmidt number is equal to unity
Last Answer : (C) For Laminar flow over a plate of length L, the local mass transfer coefficient at a distance L from the leading edge is 1.5 × 10 -2m/s. Then the average mass transfer co-efficient for the plate is 2 × 10 -2m/s
Description : Fenske-Underwood equation used for calculating the minimum number of theoretical plates in distillation column is valid for (A) Constant molal overflow (B) Total reflux (C) Constant relative volatility (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : Pick out the correct statement. (A) The slope of the stripping line is always less than unity (B) For a given separation in a binary distillation column, with increase in reflux ratio ( ... (D) Kremser-Brown-Souder's equation is used to calculate the efficiency of a plate tower
Last Answer : C) In Ponchon-Savarit method of no. of theoretical plate determination, the stripping and rectifying operating lines are vertical at total reflux
Description : McCabe-Thiele method of binary distillation does not assume that the (A) Sensible heat changes are negligible compared with latent heat changes (B) Molar latent heats of all components are equal (C) Heat of mixing is negligible (D) None of these
Last Answer : (D) None of these
Description : If f = moles of vapour present per mole of feed, then the slope of feed line is (McCabe-Thiele method) (A) (1 - f)/f (B) - (f - 1)/f (C) -1/f (D) -f/(1 - f)
Last Answer : (C) -1/f
Description : In McCabe-Thiele method, at infinite reflux ratio (A) The overhead product is minimum (B) Both the operating lines coincide with diagonal (C) Both (A) and (B) (D) Neither (A) nor (B)
Last Answer : (A) The overhead product is minimum
Description : In McCabe-Thiele method, at infinite reflux ratio (A) Number of plates is maximum (B) Overhead product is maximum (C) Both the operating lines coincide with the diagram (D) None of these
Last Answer : (C) Both the operating lines coincide with the diagram
Description : The McCabe ΔL law states that the (A) Molar heats of vaporisation of components are nearly equal (B) Linear crystal growth rate depends on the degree of super-saturation (C) Linear ... does not depend on the crystal size (D) Linear crystal growth rate depends on the crystal size
Last Answer : (C) Linear crystal growth rate does not depend on the crystal size
Description : Humidity chart is useful for the solution of problems concerning condensation, vaporisation and air conditioning. At a given dry bulb temperature, value of humidity obtained from the humidity chart directly, is in ... (A) Molal (B) Relative (C) Percentage (D) None of these
Last Answer : (A) Mola
Description : Trouton's ratio is given by (where λb, = molal heat of vaporisation of a substance at its normal boiling point, kcal/kmol Tb = normal boiling point, °K) (A) λb/Tb (B) Tb/λb (C) √(λb/Tb) (D) √(Tb/λb)
Last Answer : (A) λb/Tb
Description : Gibbs free energy per mole for a pure substance is equal to the (A) Latent heat of vaporisation (B) Chemical potential (C) Molal boiling point (D) Heat capacity
Last Answer : (B) Chemical potential
Description : Which of the following unit operations makes use of Thiele-Geddes equation? (A) Liquid-liquid extraction (B) Solid-liquid extraction (C) Multi-component absorption with chemical reaction (D) Multi-component distillation
Last Answer : (D) Multi-component distillation
Description : Pick out the wrong statement. (A) Minimum number of degree of freedom of a system is zero (B) Degree of freedom of a system containing a gaseous mixture of helium, carbon ... ) Enthalpy and internal energy change is zero during phase change processes like melting, vaporisation and sublimation
Last Answer : (D) Enthalpy and internal energy change is zero during phase change processes like melting, vaporisation and sublimation
Description : Entropy change of the reaction, H2O (liquid) → H2O (gas), is termed as the enthalpy of (A) Solution (B) Vaporisation (C) Formation (D) Sublimation
Last Answer : (B) Vaporisation
Description : Specific __________ does not change during a phase change (e.g. sublimation, melting, vaporisation etc.). (A) Entropy (B) Internal energy (C) Enthalpy (D) Gibbs free energy
Last Answer : (D) Gibbs free energy
Description : Calculate the enthalpy of vaporisation per mole for ethanol. Given `DeltaS = 109.8 J K^(-1) mol^(-1)` and boiling point of ethanol is `78.5^(@)`.
Last Answer : Calculate the enthalpy of vaporisation per mole for ethanol. Given `DeltaS = 109.8 J K^(-1) mol^(-1)` ... KJ mol^(-1)` D. Some more data is required
Description : If the enthalpy of vaporisation of water is `186.5 J mol^(-1)`, then entropy of its vaporisation will be
Last Answer : If the enthalpy of vaporisation of water is `186.5 J mol^(-1)`, then entropy of its vaporisation will be A. `0.5 ... (-1)` D. `2.0KJK^(-1)"mole"^(-1)`
Description : The correct order of enthalpy of vaporisation of noble gases is
Last Answer : The correct order of enthalpy of vaporisation of noble gases is A. `Xe gt Kr gt Ar Ne gt He` B. `Xe gt Ar ... gt Xe` D. `Ne gt Xe gt Kr gt He gt Ar`
Description : The dimension of diffusivity is same as that of the (A) Density (B) Molal concentration (C) Kinematic viscosity (D) Velocity head
Last Answer : (C) Kinematic viscosity
Description : For a multi-component system, the term chemical potential is equivalent to the (A) Molal concentration difference (B) Molar free energy (C) Partial molar free energy (D) Molar free energy change
Last Answer : (C) Partial molar free energy
Description : Which of the following is an extensive property of a system? (A) Heat capacity (B) Molal heat capacity (C) Pressure (D) Concentration
Last Answer : A) Heat capacity
Description : Heat sensitive materials with very high latent heat of vaporisation may be economically separated using (A) Liquid extraction (B) Distillation (C) Evaporation (D) Absorption
Last Answer : (A) Liquid extraction
Description : Absorption/evolution of heat during conversion of a substance from one allotropic form to another is termed as the heat of (A) Sublimation (B) Fusion (C) Transition (D) Vaporisation
Last Answer : C) Transition
Description : For a distillation column operating at minimum reflux, the (A) Concentration of liquid and vapour leaving a plate will be same (B) Reflux ratio will be maximum (C) Number of plates required will be maximum
Last Answer : (C) Number of plates required will be maximum
Description : __________ extractor is used for the concentration of radioactive nuclear waste. (A) Pulsed column (B) Sieve plate (C) Mixer-settler (D) Bollman
Last Answer : (A) Pulsed column
Description : Pick out the wrong statement (A) A horizontal line on the humidity chart indicates the temperature changes at constant molal humidity (B) When water is cooled from 80 to 70°C by exposure ... & air cannot be increased by either reducing the mixture temperature or by increasing the total pressure
Last Answer : (D) Relative saturation of unsaturated mixture of water vapor & air cannot be increased by either reducing the mixture temperature or by increasing the total pressure
Description : The assumption made in Elis method in distillation is that enthalpy concentration lines of vapor and liquid are (A) Parallel (B) Straight (C) Both parallel and straight (D) Neither parallel nor straight
Last Answer : (C) Both parallel and straight
Description : Define molal elevation constant or ebullioscopic constant.
Last Answer : Ans:- It is equal to the elevation in boiling point of1 molar soln. i.e one mole of a solute dissolved in 1 kg of the solvent.
Description : Absorption factor method is used to calculate the number of ideal stages, when (A) Operating line lies above the equilibrium line (B) Operating line lies below the equilibrium line (C) Both operating and equilibrium lines are parallel (D) Pressure drop in the column is very high
Last Answer : (C) Both operating and equilibrium lines are parallel
Description : Pick out the correct statement. (A) A chemical reaction accompanied by absorption of heat is called an exothermic reaction (B) A chemical reaction accompanied by evolution of heat is called an ... does not change on changing the concentration units (D) Chemical equilibrium state is dynamic in nature
Last Answer : (C) The rate constant for a first order reaction does not change on changing the concentration units
Description : . Kick's law assumes that the energy required for size reduction is proportional to the logarithm of the ratio between the initial and the final diameters. The unit of Kick's constant is (A) kW. sec/kg (B) kWh/kg (C) kWh/sec. kg (D) kg/sec
Last Answer : (A) kW. sec/kg
Description : Clausius-Clapeyron Equation gives accurate result, when the (A) Vapour pressure is relatively low and the temperature does not vary over wide limits (B) Vapour obeys the ideal gas law and the latent heat of ... is negligible compared with that in the vapour state (D) All (A), (B) and (C)
Description : Which of the following is not a reversible process? (A) Expansion of an ideal gas against constant pressure (B) Atmospheric pressure vaporisation of water at 100°C (C) Solution of NaCl in water at 50°C (D) None of these
Last Answer : C) Solution of NaCl in water at 50°C
Description : Terzaghi's theory of one dimensional consolidation assumes (A) Load is applied in one direction (B) Coefficient of permeability is constant (C) Excess pore water drains out only in the vertical direction (D) All the above
Last Answer : Answer: Option D
Description : For an elliptical hole on a flat plate, if width of the hole in direction of the load decrease, Stress Concentration Factor will______ a) Increase b) Decrease c) Remains constant d) Can’t be determined. Varies from material to material
Last Answer : a) Increase
Description : The change in enthalpy per unit weight of adsorbed gas when adsorbed on gas free or "outgassed" adsorbent to from a definite concentration of adsorbate is called its (A) Integral heat of adsorption (B) Heat of wetting (C) Differential heat of adsorption (D) Heat of normal condensation
Last Answer : (A) Integral heat of adsorption
Description : The change in enthalpy, when a unit quantity of gas is absorbed by relatively large quantity of adsorbent (on which a definite concentration of the adsorbed gas already exists) is termed as the (A) ... (B) Heat of wetting (C) Integral heat of adsorption (D) None of these
Last Answer : (A) Differential heat of adsorption
Description : Isotherm on an enthalpy-concentration diagram, for an ideal solution will be a (A) Straight line (B) Sine curve (C) Parabola (D) Hyperbola
Last Answer : (A) Straight line
Description : Which of the following is true regarding IRR? A. IRR assumes reinvestment at the cost of capital. B. IRR is the discount rate when NPV is greater than zero. C. IRR is a constrained optimization method. D. IRR is the discount rate when NPV is equal to zero.
Last Answer : D. IRR is the discount rate when NPV is equal to zero.
Description : Bishop's method of stability analysis (A) Is more conservative (B) Neglects the effect of forces acting on the sides of the slices (C) Assumes the slip surface as an arc of a circle (D) All of the above
Last Answer : Answer: Option C
Description : What is the Thiele modulus of the solid catalysed first order reaction as shown in the bellow figure, if the pore diffusion offers negligible resistance to reaction? (A) < 5 (B) < 0.5 (C) > 1 (D) 5
Last Answer : (B) < 0.5
Description : If Thiele modulus is __________, then the pore diffusion resistance in a catalyst may be considered as negligible. (A) 0 (B) ∞ (C) < 0.5 (D) > 0.5
Last Answer : (C) < 0.5
Description : For a first order chemical reaction in a porous catalyst, the Thiele modulus is 10. The effectiveness factor is approximately equal to (A) 0 (B) 1 (C) 0.1 (D) 0.5
Last Answer : (C) 0.1