chemical engineering Mcqs
8051. For a stable phase at constant pressure and temperature, the fugacity of each component in a binary system _____________ as its mole fraction increases?
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A. Decreases linearly

B. Remain same

C. Decreases

D. Increases
8052. Joule-Thomson co-efficient is defined as__________________?
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A. ? = (?E/?T)H

B. ? = (?T/?P)H

C. ? = (?E/?P)H

D. ? = (?P/?T)H

8053. Critical temperature is defined as the temperature above which a gas will____________________?
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A. Not liquify (barring exceptions)

B. Immediately liquify

C. None of these

D. Never liquify however high the pressure may be
8054. 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__________________?
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A. Henrys law

B. Called Lewis-Randall rule

C. None of these

D. The statement as per Gibbs-Helmholtz

8055. A solute distributes itself between two non-miscible solvents in contact with each other in such a way that, at a constant temperature, the ratio of its concentrations in two layers is constant, irrespective of its total amount. This is_________________?
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A. None of these

B. The distribution law

C. Followed from Margules equation

D. A corollary of Henrys law

8056. A gas has a volume of 27.3 c.c. at 0C. Its volume at 10C (if pressure remains unchanged) will be _____________ c.c?
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A. 2.73

B. 273

C. 28.3

D. 283

8057. The equilibrium constant for a chemical reaction at two different temperatures is given by__________________?
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A. Kp2/Kp1 = (1/R) (1/T2 1/T1)

B. Kp2/Kp1 = (?H/R) (1/T2 1/T1)

C. Kp2/Kp1 = (?H/R) (1/T2 1/T1)

D. Kp2/Kp1 = ?H (1/T2 1/T1)

8058. Second law of thermodynamics is concerned with the_________________?
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A. Non-cyclic processes only

B. Direction of energy transfer

C. Amount of energy transferred

D. Irreversible processes only

8059. The energy of activation of exothermic reaction is_________________?
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A. Negative

B. Not possible to predict

C. Very large compared to that for endothermic reaction

D. Zero

8060. Maximum work that could be secured by expanding the gas over a given pressure range is the _____________ work?
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A. None of these

B. Isentropic

C. Adiabatic

D. Isothermal
8061. A system undergoes a change from a given initial state to a given final state either by an irreversible process or by a reversible process, then (where, ? S1 and ? SR are the entropy changes of the system for the irreversible and reversible processes respectively) ?
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A. ? S1 is always > ? SR

B. ? S1 is always ? SR

C. ? S1 is always = ? SR

8062. In jet refrigerators, the refrigerating fluid is practically always_________________?
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A. Brine

B. Water

C. Ammonia

D. Freon

8063. Pick out the Clausius-Clapeyron equation from the following?
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A. None of these

B. ?F = ?H + T [?(?F)/?T]P

C. ln P = (?H/RT) + constant

D. dP/dT = ?H/T?V

8064. Out of the following refrigeration cycles, which one has maximum COP ?
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A. Ordinary vapor compression cycle

B. Carnot cycle

C. Air cycle

D. Vapor compression with a reversible expansion engine

8065. The reaction A (l) ? R(g) is allowed to reach equilibrium conditions in an autoclave. At equilibrium, there are two phases, one a pure liquid phase of A and the other a vapor phase of A, R and S. Initially A alone is present. The numbers of degrees of freedom are ?
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A. 3

B. 0

C. 1

D. 2
8066. Air-refrigeration cycle________________?
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A. Is the most efficient of all refrigeration cycles

B. Has very low efficiency

C. Requires relatively large quantities of air to achieve a significant amount of refrigeration

D. Both B. and C
8067. In case of a reversible process (following pvn = constant), work obtained for trebling the volume (v1 = 1 m3 and v23 m3) is maximum, when the value of n is_________________?
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A. y = 1.44

B. 1

C. 0

D. 1.66

8068. Pressure-enthalpy chart is useful in refrigeration. The change in internal energy of an ideal fluid used in ideal refrigeration cycle is_____________________?
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A. Zero

B. Negative

C. Infinity

D. Positive

8069. Enthalpy of a gas depends upon its___________________?
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A. Mass

B. Pressure

C. Volume

D. Temperature
8070. In vapour compression refrigeration system, if the evaporator temperature and the condenser temperatures are -13C and 37C respectively, the Carnot COP will be________________?
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A. 0.168

B. 6.2

C. 5.2

D. Data insufficient, cant be found out

8071. For the gaseous phase chemical reaction, C2H4(g) + H2O(g) ? C2H5OH(g), the equilibrium conversion does not depend on the________________?
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A. Pressure

B. Temperature

C. None of these

D. Steam to ethylene ratio

8072. Chemical engineering thermodynamics is concerned with the ____________ in/of chemical processes?
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A. Reaction mechanism

B. None of these

C. Calculation of rates

D. Energy transformation from one form to another
8073. If the heat of solution of an ideal gas in a liquid is negative, then its solubility at a given partial pressure varies with the temperature as__________________?
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A. solution

B. Solubility increases as temperature decreases

C. Solubility is independent of temperature

D. Solubility increases or decreases with temperature depending on the Gibbs free energy change

E. Solubility increases as temperature increases

8074. Compressibility factor-reduced pressure plot on reduced co-ordinates facilitates__________________?
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A. Use of only one graph for all gases

B. Covering of wide range

C. Easier plotting

D. More accurate plotting

8075. The point at which all the three (solid, liquid and gas) phases co-exist, is known as the ____________ point?
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A. Triple

B. Boyle

C. Freezing

D. Boiling

8076. Critical compressibility factor for all substances___________________?
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A. Are more or less constant (vary from 0.2 to 0.3)

B. Vary as square of the absolute temperature

C. None of these

D. Vary as square of the absolute pressure

8077. Free energy change of mixing two liquid substances is a function of the__________________?
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A. Temperature only

B. All A, B. and C

C. Concentration of the constituents only

D. Quantities of the constituents only

8078. A two stage compressor is used to compress an ideal gas. The gas is cooled to the initial temperature after each stage. The intermediate pressure for the minimum total work requirement should be equal to the _____________ mean of P1 and P2.(where, P1 and P2 are initial and final pressures respectively) ?
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A. Logarithmic

B. Geometric

C. Arithmetic

D. Harmonic

8079. Gibbs free energy per mole for a pure substance is equal to the__________________?
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A. Latent heat of vaporisation

B. Molal boiling point

C. Heat capacity

D. Chemical potential
8080. Compressibility factor for almost all the gases are approximately same at the same__________________?
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A. Critical pressure and critical temperature

B. Reduced pressure and reduced temperature

C. Pressure and temperature

D. None of these

8081. The quantitative effect of temperature on chemical equilibrium is given by the____________________?
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A. None of these

B. Le-Chateliers principle

C. Arrhenius equation

D. Vant-Hoff equation
8082. A refrigerator may be termed as a____________________?
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A. Heat pump

B. Carnot engine

C. None of these

D. Heat engine

8083. Heat of reaction at constant volume is identified with _____________ change?
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A. Enthalpy

B. Neither A. nor B

C. Either A. or B

D. Internal energy
8084. The equation DU = Tds PdV is applicable to infinitesimal changes occuring in_________________?
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A. A closed system of constant composition

B. A closed system with changes in composition

C. An open system of constant composition

D. An open system with changes in composition

8085. For a thermodynamic system containing x chemical species, the maximum number of phases that can co-exist at equilibrium is_________________?
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A. x

B. x + 1

C. x + 3

D. x + 2
8086. The necessary condition for phase equilibrium in a multiphase system of N components is that the____________________?
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A. Sum of the chemical potentials of any given component in all the phases should be the same

B. Chemical potentials of all components should be same in a particular phase

C. Chemical potentials of a given component should be equal in all phases

D. None of these

8087. In an ideal refrigeration cycle, the change in internal energy of the fluid is_____________?
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A. Either of the above three; depends on the nature of refrigerant

B. #NAME?

C. #NAME?

D. 0
8088. An isentropic process is carried out at constant____________________?
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A. Temperature

B. Pressure

C. All (A), B. and (C)

D. Volume
8089. Adiabatic compression of a saturated water vapour makes it ____________________ ?
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A. Supersaturated

B. Superheated

C. Both A. and B

D. Neither A. nor B

8090. In an ideal gas mixture, fugacity of a species is equal to its___________________?
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A. None of these

B. Chemical potential

C. Vapor pressure

D. Partial pressure
8091. _____________ calorimeter is normally used for measuring the dryness fraction of steam, when it is very low?
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A. Bucket

B. Throttling

C. A combination of separating & throttling

D. Separating

8092. Solubility of a substance which dissolves with an increase in volume and liberation of heat will be favoured by the_______________?
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A. High pressure and low temperature

B. Low pressure and low temperature

C. Low pressure and high temperature

D. High pressure and high temperature

8093. Gibbs free energy of a pure fluid approaches _____________ as the pressure tends to zero at constant temperature?
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A. None of these

B. Zero

C. Infinity

D. Minus infinity
8094. In case of vapour compression refrigeration system, elevating the evaporator temperature (keeping the condenser temperature constant) results in_____________?
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A. Enhanced COP

B. No change in the value of COP

C. Increased or decreased COP; depending upon the type of refrigerant

D. Decreased COP

8095. Gibbs-Duhem equation relates composition in liquid phase and the _____________ at constant temperature & pressure?
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A. Partial pressure

B. Fugacity

C. All (A), (B), and (C)

D. Activity co-efficient

8096. Generation of heat by friction is an example of a/an ________________ change?
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A. Reversible

B. Irreversible

C. Adiabatic

D. Isothermal

8097. For an exothermic reaction ____________________?
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A. Only enthalpy change (?H) is negative

B. Only internal energy change (?E) is negative

C. Both ?H and ?E are negative

D. Enthalpy change is zero

8098. The change in __________ is equal to the reversible work for compression in steady state flow process under isothermal condition?
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A. Gibbs free energy

B. Helmholtz free energy

C. Internal energy

D. Enthalpy

8099. Compressibility factor of a gas is___________________?
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A. Not a function of its pressure

B. Unity, if it follows PV = nRT

C. Not a function of its nature

D. Not a function of its temperature

8100. Linde gas liquefaction process employs cooling ____________________?
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A. By throttling

B. By expansion in an engine

C. At constant pressure

D. None of these