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This section includes 838 Mcqs, each offering curated multiple-choice questions to sharpen your Chemical Engineering knowledge and support exam preparation. Choose a topic below to get started.
351. |
The accentric factor of a materical, 'ω', is defined as ω = -log10(Prsat)Tr⁻¹ = 0.7, where, Prsat = reduced vapor pressure, Tr = reduced temperature. The value of accentric factor is always |
A. | > 2 |
B. | < 1 |
C. | > 1 |
D. | < 3 |
Answer» C. > 1 | |
352. |
The ammonia synthesis reaction represented by N₂ + 3H₂ ⇋ 2NH₃ ; ΔH = - 22.4 kcal, is |
A. | Endothermic |
B. | Exothermic |
C. | Isothermal |
D. | Adiabatic |
Answer» C. Isothermal | |
353. |
The equation relating E, P, V and T which is true for all substanes under all conditions is given by (∂E/∂V)T = T.(∂P/∂T)H - P . This equation is called the |
A. | Maxwell |
B. | Thermodynamic equation of state |
C. | Equation of state |
D. | Redlich-Kwong equation of state |
Answer» C. Equation of state | |
354. |
Sublimation temperature of dry ice (solid CO₂) is __________ °C. |
A. | -273 |
B. | 0 |
C. | -78 |
D. | 5 |
Answer» D. 5 | |
355. |
Melting of ice is an example of an __________ process. |
A. | adiabatic |
B. | isothermal |
C. | isometric |
D. | none of these |
Answer» C. isometric | |
356. |
Which law of the thermodynamics provids basis for measuring the thermodynamic property ? |
A. | First law |
B. | Zeroth law |
C. | Third law |
D. | Second law |
Answer» C. Third law | |
357. |
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 |
A. | the distribution law. |
B. | followed from Margule's equation. |
C. | a corollary of Henry's law. |
D. | none of these. |
Answer» B. followed from Margule's equation. | |
358. |
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 |
A. | solubility increases as temperature increases. |
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 of solution. |
Answer» C. solubility is independent of temperature. | |
359. |
Molar heat capacity of water in equilibrium with ice at constant pressure is __________ Kcal/kg mole . °K$ |
A. | 0 |
B. | ‚àû |
C. | 50 |
D. | 100 |
Answer» C. 50 | |
360. |
Co-efficient of Performance (COP) of a refrigerator is the ratio of the |
A. | work required to refrigeration obtained. |
B. | refrigeration obtained to the work required. |
C. | lower to higher temperature. |
D. | higher to lower temperature. |
Answer» C. lower to higher temperature. | |
361. |
The partial pressure of each constituent present in an alloy is __________ the total vapor pressure exerted by the alloy. |
A. | less than |
B. | equal to |
C. | more than |
D. | either (b) or (c); depends on the type of alloy |
Answer» B. equal to | |
362. |
Third law of thermodynamics is concerned with the |
A. | value of absolute entropy. |
B. | energy transfer. |
C. | direction of energy transfer. |
D. | none of these. |
Answer» B. energy transfer. | |
363. |
In any spontaneous process, the __________ free energy decreases. |
A. | Helmholtz |
B. | Gibbs |
C. | both a & b |
D. | neither 'a' nor 'b' |
Answer» D. neither 'a' nor 'b' | |
364. |
Which of the following is an undesirable characteristics of a refrigerant ? |
A. | It should be non-explosive. |
B. | It should have a sub-atmospheric vapor pressure at the temperature in refrigerator coils. |
C. | Its vapor pressure at the condenser temperature should be very high. |
D. | None of these. |
Answer» C. Its vapor pressure at the condenser temperature should be very high. | |
365. |
With increase in temperature, the atomic heat capacities of all solid elements |
A. | increases |
B. | decreases |
C. | remains unchanged |
D. | decreases linearly |
Answer» B. decreases | |
366. |
The first law of thermodynamics is a restatement of the law of conservation of |
A. | mass |
B. | energy |
C. | momentum |
D. | none of these |
Answer» C. momentum | |
367. |
The unity of Planck's constant 'h' in the equation, E = hv is |
A. | J/s |
B. | J.S |
C. | J/kmol |
D. | kmol/J |
Answer» C. J/kmol | |
368. |
A gas has a volume of 27.3 c.c. at 0°C. Its volume at 10°C (if pressure remains unchanged) will be __________ c.c.$ |
A. | 2.73 |
B. | 28.3 |
C. | 273 |
D. | 283 |
Answer» C. 273 | |
369. |
Change of state namely evaportation condensation, freezing and melting is an __________ process. |
A. | isothermal |
B. | adiabatic |
C. | isobaric |
D. | isochoric |
Answer» B. adiabatic | |
370. |
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 |
Answer» C. molal boiling point | |
371. |
Free energy changes for two reaction mechanism 'X' and 'Y are respectively - 15 and - 5 units. It implies that X is |
A. | slower than Y |
B. | faster than Y |
C. | three times slower than Y |
D. | three times faster than Y |
Answer» C. three times slower than Y | |
372. |
A nozzle is a device, which |
A. | increases kinetic energy and decreases pressure. |
B. | reduces kinetic energy and increases pressure. |
C. | reduces both kinetic energy and pressure. |
D. | increases both kinetic energy and pressure. |
Answer» B. reduces kinetic energy and increases pressure. | |
373. |
The total change in the enthalpy of a system is independent of the |
A. | number of intermediate chemical reactions involved. |
B. | pressure and temperature. |
C. | state of combination and aggregation in the beginning and at the end of the reaction. |
D. | none of these. |
Answer» B. pressure and temperature. | |
374. |
The effect of changing the evaporator temperature on COP as compared to that of changing the condenser temperature (in vapour compression refrigeration system) is |
A. | less pronounced |
B. | more pronounced |
C. | equal |
D. | data insufficient, can't be predicted. |
Answer» C. equal | |
375. |
Which of the following processes can not be made reversible even under ideal condition of operation? |
A. | Free expansion of a gas. |
B. | Compression of air in a compressor. |
C. | Expansion of steam in a turbine. |
D. | all (a), (b) & (c). |
Answer» B. Compression of air in a compressor. | |
376. |
Which is not a refrigerant ? |
A. | SO2 |
B. | NH3 |
C. | CCl2F2 |
D. | C2H4Cl2 |
Answer» E. | |
377. |
In case of the decomposition of hydroiodic acid (2HI H2 + I2), addition of H2 (at equilibrium condition) will |
A. | increase the partial pressure of I2. |
B. | decrease the partial pressure of HI. |
C. | diminish the degree of dissociation of HI. |
D. | none of these. |
Answer» D. none of these. | |
378. |
Minimum number of phases that exists in a system is 1. Number of chemical species in a colloidal system is |
A. | 1 |
B. | 4 |
C. | 2 |
D. | 3 |
Answer» D. 3 | |
379. |
Adiabatic compression of a saturated water vapour makes it |
A. | supersaturated |
B. | superheated |
C. | both (a) and (b) |
D. | neither (a) nor (b) |
Answer» C. both (a) and (b) | |
380. |
The point at which all the three (solid, liquid and gas) phases co-exist, is known as the __________ point. |
A. | freezing |
B. | triple |
C. | boiling |
D. | Boyle |
Answer» C. boiling | |
381. |
In which of the following reaction equilibria, the value of equilibrium constant Kp will be more than is Kc ? |
A. | 2HI H2 + I2 |
B. | N2O4 2NO2 |
C. | 2SO2 + O2 2SO3 |
D. | none of these |
Answer» C. 2SO2 + O2 2SO3 | |
382. |
The first law of thermodynamics is a statement of conservation of |
A. | heat |
B. | momentum |
C. | energy |
D. | work |
Answer» D. work | |
383. |
An ideal liquid refrigerant should |
A. | not have a subatmospheric vapour pressure at the temperature in the refrigerator coils. |
B. | not have unduly high vapour pressure at the condenser temperature. |
C. | both (a) and (b). |
D. | have low specific heat. |
Answer» D. have low specific heat. | |
384. |
"If different processes are used to bring about the same chemical reaction, the enthalpy change is same for all of them". This is __________ law. |
A. | Hess's |
B. | Kirchoff's |
C. | Lavoisier and Laplace |
D. | none of these |
Answer» B. Kirchoff's | |
385. |
Internal energy is equal to the heat absorbed in case of a/an __________ process. |
A. | constant volume |
B. | polytropic |
C. | adiabatic |
D. | constant pressure |
Answer» B. polytropic | |
386. |
For spontaneous changes in an isolated system (S = entropy) |
A. | ds = 0 |
B. | ds <0 |
C. | ds > 0 |
D. | ds = Constant |
Answer» D. ds = Constant | |
387. |
The expression for entropy change given by, ΔS = nR ln (V2/V1) + nCv ln (T2/T1) is valid for$ |
A. | reversible isothermal volume change. |
B. | heating of a substance. |
C. | cooling of a substance. |
D. | simultaneous heating and expansion of an ideal gas. |
Answer» E. | |
388. |
Partial molal quantities are important in the study of |
A. | ideal gases |
B. | ideal solutions |
C. | non-ideal mixtures |
D. | a pure component |
Answer» D. a pure component | |
389. |
Which of the following non-flow reversible compression processes require maximum work ? |
A. | Adiabatic process |
B. | Isothermal process |
C. | Isobaric process |
D. | All require same work |
Answer» B. Isothermal process | |
390. |
In the reaction, represented by, 2SO2 + O2 2SO3; ΔH = - 42 kcal; the forward reaction will be favoured by$ |
A. | low temperature |
B. | high pressure |
C. | both (a) and (b) |
D. | neither (a) nor (b) |
Answer» D. neither (a) nor (b) | |
391. |
Consider the reaction, C + O2 CO2 ;ΔH = - 94 kcal. What will be the value of ΔH for the reaction CO2 C + O2 ?$ |
A. | -94 kcal |
B. | + 94 kcal |
C. | > 94 kcal |
D. | < -94 kcal |
Answer» C. > 94 kcal | |
392. |
The entropy change in a reversible isothermal process, when an ideal gas expands to four times its initial volume is |
A. | R loge 4 |
B. | R log10 4 |
C. | Cv log10 4 |
D. | Cv loge 4 |
Answer» B. R log10 4 | |
393. |
One mole of nitrogen at 8 bar and 600 K is contained in a piston-cylinder arrangement. It is brought to 1 bar isothermally against a resisting pressure of 1 bar. The work done (in Joules) by the gas is |
A. | 30554 |
B. | 10373 |
C. | 4988.4 |
D. | 4364.9 |
Answer» C. 4988.4 | |
394. |
The number of degrees of freedom for a mixture of ice and water (liquid) are |
A. | 2 |
B. | 3 |
C. | 1 |
D. | 0 |
Answer» D. 0 | |
395. |
The chemical potential of any constituent of an ideal solution depends on the __________ of the solution. |
A. | temperature |
B. | pressure |
C. | composition |
D. | all (a), (b) and (c) |
Answer» E. | |
396. |
On a P-V diagram of an ideal gas, suppose a reversible adiabatic line intersects a reversible isothermal line at point A. Then at a point A, the slope of the reversible adiabatic line (∂P/∂V)s and the slope of the reversible isothermal line (∂P/∂V)T are related as (where, y = Cp/Cv)$ |
A. | (∂P/∂V)S = (∂P/∂V)T |
B. | (∂P/∂V)S = [(∂P/∂V)T]Y |
C. | (∂P/∂V)S = y(∂P/∂V)T |
D. | (∂P/∂V)S = 1/y(∂P/∂V)T |
Answer» D. (‚àÇP/‚àÇV)S = 1/y(‚àÇP/‚àÇV)T | |
397. |
Pressure-enthalpy chart is useful in refrigeration. The change in internal energy of an ideal fluid used in ideal refrigeration cycle is |
A. | positive |
B. | negative |
C. | zero |
D. | infinity |
Answer» D. infinity | |
398. |
Kopp's rule is used to calculate the heat capacity of |
A. | solids |
B. | liquids |
C. | gases |
D. | all (a), (b) & (c) |
Answer» B. liquids | |
399. |
Refrigeration cycle |
A. | violates second law of thermodynamics. |
B. | involves transfer of heat from low temperature to high temperature. |
C. | both (a) and (b). |
D. | neither (a) nor (b). |
Answer» C. both (a) and (b). | |
400. |
A closed system is cooled reversibly from 100°C to 50°C. If no work is done on the system$ |
A. | its internal energy (U) decreases and its entropy (S) increases. |
B. | U and S both decreases |
C. | U decreases but S is constant. |
D. | U is constant but S decreases. |
Answer» C. U decreases but S is constant. | |