Description : Pick out the correct statement. (A) For identical gas flow rates, less pressure drop occurs through a plate tower than through a packed tower (B) Plate column can handle greater liquid loads without flooding than packed ... duty, plate columns weigh less than packed columns (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : Pick out the wrong statement. (A) Packed towers are preferred for vacuum operation, because the pressure drop through the packing is less and they (packings) also lessen the ... of liquid, problem of channelling, loading & flooding is generally encountered in packed towers
Last Answer : (C) Diameter of randomly packed tower is normally more than 1.2 metres
Description : The main reason for dividing a tall packed tower into series of small towers is to (A) Minimise the overall pressure drop (B) Avoid flooding (C) Reduce liquid hold up (D) Avoid channelling
Last Answer : (D) Avoid channelling
Description : Out of the following gas-liquid contacting devices, for a given set of operating conditions, gas pressure drop is the least in __________ tower. (A) Wetted wall (B) Bubble cap (C) Perforated tray (D) Packed
Last Answer : (A) Wetted wall
Description : Pick out the wrong statement: (A) Change in barometric pressure does not affect the relative humidity (B) In case of a packed tower, the operating velocity is about half of the ... (D) The equilibrium moisture content of the solid can be reduced by increasing the absolute humidity
Last Answer : (D) The equilibrium moisture content of the solid can be reduced by increasing the absolute humidity
Description : With increase in the liquid flow rate at a fixed gas velocity in a randomly packed counter current gas-liquid absorption column, the gas pressure drop (A) Decreases (B) Remains unchanged (C) Increases (D) Decreases exponentially
Last Answer : (C) Increases
Description : Very tall packed towers are divided into series of beds to (A) Reduce the overall pressure drop (B) Avoid channelling (C) Reduce liquid hold-up (D) Avoid flooding
Last Answer : (B) Avoid channelling
Description : Plate towers are preferred to packed towers, when large temperature changes are involved, because of the reason that the (A) Packing may be crushed due to thermal expansion/contraction of the ... C) Viscosity variation of the fluids may cause channelling/flooding (D) None of these
Last Answer : (A) Packing may be crushed due to thermal expansion/contraction of the components of the equipments
Description : At the same gas flow rate, the pressure drop in a packed tower being irrigated with liquid __________ that in dry packed tower. (A) Is greater than (B) Is lower than (C) Is same as (D) Cannot be predicted as data are insufficient
Last Answer : (A) Is greater than
Description : Operating velocity in a packed tower is usually __________ the flooding velocity. (A) Half (B) Twice (C) Equal to (D) More than
Last Answer : (A) Half
Description : Use of raschig rings in place of crushed stones as packing in packed beds (other things being same) (A) Increases pressure drop, increases surface area (B) Increases pressure drop, decreases ... (C) Decreases pressure drop, increases surface area (D) Decreases pressure drop, decreases surface area
Last Answer : (C) Decreases pressure drop, increases surface area
Description : In a boundary layer developed along the flow, the pressure decreases in the downstream direction. The boundary layer thickness in this case will (A) Decrease gradually (B) Increase gradually (C) Increase rapidly (D) Remain constant
Last Answer : (B) Increase gradually
Description : Channelling in a packed tower results from the (A) High pressure drop (B) Maldistribution of liquid (C) Non-uniformity of packing (D) Both (B) and (C)
Last Answer : (D) Both (B) and (C)
Description : A packed tower compared to a plate tower for a particular mass transfer operation (A) Incurs smaller pressure drop (B) Allows installation of cooling coils (C) Is less costly when built in large sizes/diameters (D) Is more suitable, if suspended solids are present in fluid stream
Last Answer : (A) Incurs smaller pressure drop
Description : The reason for preferring packed towers over plate towers in distillation practice is that the packed tower operation gives (A) Low pressure drop and high hold up (B) High pressure drop and low hold ... C) Low pressure drop and low hold up (D) High pressure drop and high hold up
Last Answer : (C) Low pressure drop and low hold up
Description : Pressure drop through plate tower as compared to that through packed tower, for the same duty will be (A) Less (B) More (C) Equal (D) Either (A) or (B); depends on the packing height
Last Answer : (B) More
Description : For a spontaneous natural process at constant temperature and pressure, the free energy of the system always (A) Increases (B) Decreases (C) Remain constant (D) Increases to a maximum before decreasing
Last Answer : : Option A
Description : 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 ... increases. (A) Decreases (B) Decreases exponentially (C) Increases (D) Remain constant
Description : With increase in reduced temperature, the fugacity co-efficient of a gas at constant reduced pressure (A) Increases (B) Decreases (C) Remain same (D) Decreases linearly
Last Answer : (A) Increases
Description : Assuming all other parameters remain constant, what happens to the pressure of a gas when the volume of the gas is increased? w) increases x) decreases y) fluctuates sinusoidally z) remains the same
Last Answer : ANSWER: X -- DECREASES
Description : Minimum possible diameter of a packed column is decided mainly bythe (A) Flooding (B) Gas viscosity (C) Liquid density (D) Liquid hold up
Last Answer : (A) Flooding
Description : The filtrate flow rate in constant pressure filtration (A) Continuously increases (B) Continuously decreases (C) Remain constant throughout (D) May increase or decrease; depends on the pressure
Last Answer : (B) Continuously decreases
Description : For water, when the pressure increases, the viscosity (A) Also increases (B) Decreases (C) Remain constant (D) First decreases, and then increases
Last Answer : (D) First decreases, and then increases
Description : With increase in temperature, the vapor pressure of liquids (A) Increases (B) Increases linearly (C) Decreases (D) Remain constant
Description : With increase in the ratio of orifice diameter to pipe diameter in case of an orificemeter, the overall pressure loss (A) Decreases (B) Increases (C) Remain constant (D) Increases linearly
Last Answer : (C) Remain constant
Description : With the increase in depth, the hydrostatic pressure in an un-accelerated incompressible fluid (in a constant gravitational field) (A) Decreases (B) Increases linearly (C) Increases exponentially (D) Remain constant
Last Answer : (B) Increases linearly
Description : For a stable phase at constant pressure and temperature, the fugacity of each component in a binary system __________ as its mole fraction increases. (A) Decreases (B) Increases (C) Remain same (D) Decreases linearly
Last Answer : (B) Increases
Description : With increase in the mass velocity of the gas, the rate of drying during the constant rate period __________, if the conduction and radiation through the solid are negligible. (A) Increases (B) Decreases (C) Remain same
Description : With increase in the pressure drop across the cake, the specific cake resistance for the compressible sludge (A) Increases (B) Decreases (C) Remains constant (D) Increases linearly
Description : In a packed absorption tower, if the equilibrium and operating lines are both straight lines, then the ratio, HETP/HTUOG __________ the absorption factor. (A) Increases with increase in (B) Is one at unity value of (C) Both (A) and (B) (D) Neither (A) nor (B)
Last Answer : (C) Both (A) and (B)
Description : In an isothermal atmosphere, the pressure (A) Decreases linearly with elevation (B) Remain constant (C) Varies in the same way as the density (D) Increases exponentially with elevation
Last Answer : Answer: Option C
Description : bulk modulus of elasticity with increase in pressure (A) Increases (B) Decreases (C) Remain constant (D) Increases first up to certain limit and then decreases
Last Answer : Answer: Option A
Description : A gas (density = 1.5 kg/m3 , viscosity = 2 10 -5 kg/m.s) flowing through a packed bed (particle size = 0.5 cm, porosity = 0.5) at a superficial velocity of 2 m/s causes a pressure drop of 8400 Pa/m. The ... flowing at 3 m/s will be (A) 8400 Pa/m (B) 12600 Pa/m (C) 18900 Pa/m (D) 16800 Pa/m
Last Answer : (B) 12600 Pa/m
Description : Boiling point elevation of an ideal solution (A) Increases rapidly with temperature rise (B) Decreases rapidly with temperature rise (C) In independent of pressure (D) Both (B) and (C)
Last Answer : (A) Increases rapidly with temperature rise
Description : Which of the following provides maximum contact surface for a liquidvapour system? (A) Packed tower (B) Bubble-cap plate column (C) Sieve-plate column (D) Wetted wall column
Last Answer : (A) Packed tower
Description : Temperature of the product during ultrafine grinding (A) Increases (B) Decreases (C) Remain constant (D) May increase or decrease; depends on the material being ground
Description : All resistances during washing of cake (A) Increases (B) Decreases (C) Remain constant (D) None of these
Description : With lapse of time, the overhead composition of light component in case of batch distillation with constant reflux (A) Increases (B) Decreases (C) Remain same (D) May increase or decrease; depends on system
Last Answer : (B) Decreases
Description : For shell and tube heat exchanger, with increasing heat transfer area, the purchased cost per unit heat transfer area (A) Increases (B) Decreases (C) Remain constant (D) Passes through a maxima
Last Answer : (D) Passes through a maxima
Description : The film thickness for laminar film condensation on vertical surface __________ from top to bottom. (A) Cumulatively increases (B) Cumulatively decreases (C) Remain constant (D) And the surface conductance increase
Last Answer : (A) Cumulatively increases
Description : With increase in temperature, the thermal conductivity of non-metallic amorphous solids (A) Decreases (B) Increases (C) Remain constant (D) First decreases upto certain temperature and then increases
Description : The absorptivity of a grey body at a given temperature __________ with increasing wavelength of radiation. (A) Increases (B) Decreases (C) Remain constant (D) May increase or decrease; depends on the material
Last Answer : (D) May increase or decrease; depends on the material
Description : In a single evaporator system, the steam economy __________ by creating vacuum in the evaporator. (A) Increases (B) Decreases (C) Remain constant (D) May increase or decrease, depends on the vacuum
Description : With increase in temperature, the thermal conductivity of most liquids (A) Increases (B) Decreases (C) Remain same (D) First increases upto a certain temperature and then becomes constant
Last Answer : (C) Remain same
Description : C.V. (kcal/Nm3 ) of gaseous fuels __________ with increase in molecular weight. (A) Decreases (B) Increases (C) Remain constant (D) May increase or decrease, depends on combustibles
Last Answer : (D) May increase or decrease, depends on combustibles
Description : During coking of coal, the ash content (percentage) (A) Increases (B) Decreases (C) Remain constant (D) None of these
Description : With increase in the temperature, viscosity of a liquid (A) Increases (B) Decreases (C) Remain constant (D) May increase or decrease; depends on the liquid
Description : The amount of chemical coagulant added for treatment of polluted water __________ with increase in temperature of the polluted water to be treated. (A) Decreases (B) Increases (C) Remain constant (D) May increase or decrease; depends on the chemical characteristics of polluted water
Last Answer : (A) Decreases
Description : When a catalyst increases the rate of forward reaction, the value of rate constant (A) Increases (B) Decreases (C) Remain same (D) Becomes infinite
Description : With increase in initial concentration, the fractional conversion of a first order reaction in a given time (A) Increases (B) Decreases (C) Remain constant (D) Unpredictable