Chemical Engineering Basic Questions and Answers

Chemical Engineering MCQ Questions and Answers. Prepare Top Interview Questions and Answers for Civil Engineering Interview Questions, Mechanical Engineering Interview Questions, Electrical Engineering Interview Questions, Online preparation tests for Engineering Students. Chemical Engineering Interview and Multiple choice Questions and Answers

Chemical Engineering Basics

1. Free energy, fugacity, and activity co-efficient are all affected by changes in the temperature. The fugacity coefficient of a gas at constant pressure ______with the increase of reduced temperature. 

2. For a spontaneous process, free energy 

3. Near their critical temperatures, all gases occupy volumes _______ that of the ideal gas 

4.  Work done is a

5.  The free energy change for a chemical reaction is given by (where K = equilibrium constant) 

6. Entropy is a measure of the _________ of a system 

7. Heating of water under atmospheric pressure is an ________ process 

8. What is the number of degrees of freedom for liquid water in equilibrium with a mixture of nitrogen and water vapor? 

9. Solubility of a substance which dissolves with an increase in volume and liberation of heat vi1l be favored by the 

10.  Internal energy change of a system over one complete cycle in a cyclic process 

Chemical Reaction Engineering

1. Pick out the correct statement 

A. A lower temperature favors the reaction of lower activation energy

B.  Pore volume and porosity of a catalyst is measured by Brunaver-Emmet-Teller (BET) technique

C. The dispersion number for a reactor/vessel is uL/D

D. The rate-controlling step in a reaction involving many steps is the fastest step

Ans: A

2. A batch reactor is characterized by 

3. ‘Unreacted core model’ represents the reaction involving 

4. A photochemical reaction is _______________ light 

5. The rate constant of a chemical reaction increases by increasing the 

6. When a catalyst increases the rate of forwarding reaction, the value of the rate constant 

7. In case of_______________ reactions, the reaction rate does not decrease appreciably as the reaction proceeds

8. For nearly isothermal operation involving large reaction time in a liquid-phase reaction, the most suitable reactor is a ________________ reactor

9. In a/an ________________ reactor, there is exchange of heat with the surroundings with sizeable temperature variation 

10. Pick out the wrong statement 

A. In a semi-batch reactor, one reactant is charged batch-wise, while the other reactant is fed continuously

B. In a batch reactor, which is exclusively used for liquid-phase reactions; temperature pressure and composition may vary with time

C. In a continuous flow reactor both the reactants amid the products flow out continuously

D. In a continuous flow reactor, uniform concentration can not be maintained throughout the vessel even in a well-agitated system

Ans: D

Chemical Process

1. Concentration of hydrogen peroxide is done by

2. Which of the following is not produced on a commercial scale from seawater?

3. Heating of ______________ to 120°C, produces plaster of Paris

4. The only commercial Fischer-Tropsch plant for producing liquid hydrocarbon fuel from coal is located at

5. Which of the following has sodium bicarbonate as its main constituent?

6. Paper grade bamboo contains about _____________ percent cellulose

7. Lurgi coal gasifier is a pressurised ______________ bed reactor

8. Carboxymethyl cellulose (CMC) is added in detergents to act as a/an

9. Raw materials for the ‘Solvay Process’ for the manufacture of the soda ash are

10. Heliuni is produced on a commercial scale from

Chemical Mechanics

1. For an ideally incompressible fluid, the Mach number will be

A. 1

B. 1.5

C. 2

D. 5

Ans: A

2. Velocity distribution for flow between two fixed parallel plates

A. varies parabolically across the section

B. is zero at the plates and increases linearly to the midplane

C. is constant over the entire cross-section

D. none of these

Ans: A

3. If more than two branches of pipes are to be connected at the same point, then use a/an

A. UfliOfl

B. elbow

C. tee

D. none of these

Ans: C

4. Mass velocity is independent of temperature & pressure, when the flow is

A. unsteady through unchanged cross-section

B. steady through changing cross-section

C. steady and the cross-section is unchanged

D. unsteady and the cross-section is changed

Ans: C

5. Drag force acting on a body does not depend upon the

A. density of the fluid

B. velocity of the body

C. density of the body

D. projected area of the body

Ans: C

6. Very small pressure difference (< mm water coloumn) can be most conveniently measured by a/an ____________ manometer

A. inclined tube mercury

B. U-tube water

C. U-tube mercury

D. inclined tube water

Ans: D

7. Acceleration head in a reciprocating pump

A. increases the work done during delivery stroke

B. increases the work done during suction stroke

C. does not change the work requirement of the pump

D. decreases the work done during suction stroke

Ans: C

8. Check valves are used

A. in bends

B. at high pressure

C. for controlling water flow

D.for unidirectional flow

Ans: D

9. In an incompressible fluid, the density is

A. sensible to changes in both temperature & pressure

B. not affected with moderate change in temperature & pressure

C. greatly affected only by moderate changes in temperature

D. greatly affected by moderate changes in pressure

Ans: B

10. Which of the fluid forces are not considered in Revnold’s equation of flow

A. Pressure forces

B. Compressibility forces

C. Turbulent forces

D. Viscous forces

Ans: B

Heat Transfer

1. At constant temperature, the thermal conductivities of gases with rising in pressure

2. Fruit juice (a heat-sensitive material) can be concentrated in a ________ evaporator

3. In an interphase heat transfer process, the equilibrium state corresponds to equality of temperature in the two phases, while the condition for equilibrium in an interphase mass transfer process is equality of

4. Low thermal conductivity of heat-insulating materials is due to its

5. Value of Nusselt number [Nu = (hD/k)] for the heat transfer by conduction from a droplet or a spherical particle to a surrounding stagnant film is

6. Tubes are held between top and bottom tube sheets in Calenderia type evaporator by keeping

7. Small scale evaporation is done in a

8. With an increase in temperature, the total emissivity of conductors

9. Loss of heat from untagged steam pipe to the ambient air is by

10. Heat transfer by conduction in the turbulent core of a fluid flowing through a heated pipe is negligible if the value of Prandtl number is

Mass Transfer

1. Plate efficiency

2. Molalitv is defined as the number of gui moles of solute per ________ of solvent

3. A pure drug is administered as a sphere and as a cube. The amount of drugs is the same in the two tablets. Assuming that the shape and size do not influence the mass transfer, the ratio of the rate of dissolution in water at t = o for the cubic to spherical tablet is

4. Minimum reflux ratio in a distillation column results in

5. In extraction, as the temperature increases, the area of heterogeneity (area covered by binodal curve)

6. For a single component absorber, the operating line is straight only when plotted in terms of ______ units

7. Pick out the wrong statement

8. In the case of an unsaturated mixture of gas and vapor, the percentage saturation is _______ its relative saturation

9. Flooding in a distillation column is detected by a sharp

10. _______ is concerned with the adsorption equilibria

Fertilizer Technology

1. Nitrogen content of calcium ammonium nitrate (CAN) is ______ percent

2. Which of the following is not a commercially used feedstock for the production of ammonia synthesis gas?

3. Cattail st used in steam reforming of naphtha is

4. Heating of orthophosphoric acid to about 900°C, produces

5. Rock phosphate constitutes mainly of

6. the Main component of bone ash is

7. The optimum size of the ammonia plant is ________ tons/day

8. ____ converter for ammonia synthesis, the catalyst is arranged in the form of a single continuous bed

9. Ammonium nitrate (is mixed with limestone) is not used as fertilizer as such, because

10. Phosphatic fertilisers


1. The equilibria relations in a inulticom—ponent and multiphase system can not

be calculated with the help of the

o experimental data

o empirical equations

o phase rule

o theoretical equations

Ans: C

2. Sometimes, in chemical processes, a part of the outlet stream is rejected as waste in order to keep the impurity level in the system within limits. This phenomenon is termed as the

o recycling

o purging

o bypassing

o recirculation

Ans: B

3. An azeotropic solution of two liquids has boiling point lower than either of them, when it

o is saturated

o is unsaturated

o shows positive deviation from Raoult’s law

o shows negative deviation from Raoult’s law

Ans: C

4. 2 liters of nitrogen at N.T.P. weighs gms

o 1.25

o 2.5

o 14

0 28

Ans: B

5. What is the total pressure exerted by a mixture of 0.45 kg mole of benzene, 0.44 kg mole of toluene, and 0.23 kg mole of o-x lene at 100°C, if their vapor pressures at ioo°C are 1340, 560 and 210 mmHg respectively?

o 756.2

o 780.5

o 8o1.5

o 880.5

Ans: B

6. In the case of a solution (not of a solid in a liquid), whose total volume is more than the sum of volumes of its components in their pure states, solubility is

o unchanged by the pressure change

o increased with the increase in pressure

o decreased with the increase in pressure

o independent of the temperature

Ans: C

7. Pick out the wrong statement:

o A vapor whose partial pressure is less than its equilibrium vapor pressure, is termed as a superheated vapor

o The temperature at which vapor is saturated is termed as the boiling point

o A vapor is termed as a saturated vapor if its partial pressure equals its equilibrium vapor pressure

o The difference between the existing temperature of vapor and its saturation temperature (i.e. dew point) is called its ‘degree of superheat’

Ans: B

8. If the pressure of a gas is reduced to half & its absolute temperature is doubled, then the volume of the gas will

o increase four times

o be reduced to 1/4th

o increase two times

o none of these


9. A vapor whose partial pressure is less than its equilibrium vapor pressure is called a ________ vapor

o supersaturated

o saturated

o superheated

o none of these

Ans: C

10. In the case of vapor-liquid equilibria, which of the following does not account for gas-phase deviation from ideality?

o Activity co-efficient

o Fugacity co-efficient

o Use of equation of state

o None of these

Ans: A

Chemical Engineering Thermodynamics

1. 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

o the distribution law

o a corollary of Henry’s law

o followed from Margule’s equation

o none of these

Ans: A

2. Which one is true for a throttling process?

o The inversion temperature is different for different gases

o The inversion temperature is the temperature at which the Joule-Thomson co-efficient is infinity

o The inversion temperature is the same for all gases

o A gas may have more than one inversion temperatures

Ans: A

3. Enthalpv changes over a constant pressure path are always zero for __________ gas

o a perfect

o an easily liquefiable

o a real

o any

Ans: A

4. For organic compounds, the group contribution method can be used for the estimation of

o critical properties

o thermal conductivity

o specific gravity

o specific volume

Ans: A

5. First law of thermodynamics deals with the

o irreversible processes only

o reversible processes only

o direction of energy transfer

o none of these

Ans: C

6. 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

o 10373

o 4364.9

o 4988.4

o 30554

Ans: A

7. The work done in isothermal compression compared to that in adiabatic compression will be

o more

o more or less depending upon the extent of work done

o same

o less

Ans: B

8. A solid is transformed into vapor without going to the liquid phase at

o below triple point

o always

o boiling point

o triple point

Ans: D

9. For spontaneous changes in an isolated system (S = entropy)

o ds = 0

o ds> 0

o ds < 0

o ds = Constant

Ans: B

10. When liquid and vapor phases of one component system are in equilibrium (at a given temperature and pressure), the molar free energy is

o more in liquid phase

o same in both the phases

o replaced by the chemical potential which is more in vapor phase

o more in the vapor phase

Ans: B

Fuels and Combustion

1. Fat’ coal means coal having

2. The heat of combustion of a fuel

3. In flue gas analysis by Orsat’s apparatus, carbon dioxide is absorbed by

4. With the increase in moisture content of coal, its

5. _______ has the widest inflammability limit (explosion limit) of all the gases

6. “OverfIre burning” in a furnace is a phenomenon characterized by the

7. Which of the following petrographic constituents of coal is non-coking?

8. Proximate analysis of coal determines its ______— content

9. Yield of the pitch from the distillation of high-temperature tar is around percent

10. Abrasion index of blast furnace coke should be around ____ ____ percent

Process Equipment And Plant Design

1. Pick out the wrong statement

  • o The liquid head in the downcomer should not be greater than one half the plate spacing to avoid flooding
  • o The discharge end of the downcomer must project far enough into the tray liquid so that no gas bubbles can enter the open end and bypass the bubble caps
  • o If sufficient residence time (around 8 seconds) is not provided to the downcoming liquid in the downcomer, it may entrain some vapor

Ans: A

2. The distance between the center of a rivet hole to the nearest edge of the plate is called

3. Tubes are fixed to the tube sheet (a thick circular metallic plate) by the method of tube rolling and brazing (non-removable) or ferrule connection (removable). The thickness of the tube, the sheet is normally ________ the outside diameter of the tube but in no case, it should be less than 22 mm (7/8”)

4. Wind load consideration in the design of support can be neglected, when the vessel is

5. A shell may by termed as thin if its thickness to diameter ratio is less than 0.1. The factor which can be neglected in the calculation of membrane stresses is

6. Frame thickness in the plate and frame filter press is normally in the range of _________ inches.

7. In a pressure vessel containing multiple openings of various dimensions at different parts, stress concentration at the edges of the opening is maximum which becomes negligibly small beyond the area covered by _________________ times the hole diameter

8. A minimum clearance of about __________________ mm is maintained between the distillation column wall and the bubble cap

9. Cvlinderical shell thickness of rotary drier is generally ________________ mm

10. Which of the following efficiencies can be greater than 100%?

Refractory Technology

1. Except, all other refractories are bad conductors of electricity (i.e, have low electrical conductivity)

2. Refractoriness under load (RUE) is the most important property for the refractory bricks

3. Spalling resistance of refractory can not be increased by

4. With increasing alumina content, the fusion point of high alumina refractories

5. Which is not an alumino-silicate refractory?

6. Silica bricks are attacked by basic slags at high temperatures. Which of the following is not used solely as a binding material?

7. Fireclay refractories have

8. Which is a basic refractory?

9. Which of the following is not a neutral refractory?

10. Electrical resistor bars are made of

Polymer Technology

1. ------ is a natural fiber.

2. Nylon 6 as compared to nylon 6, 6 has a lower

3. Which of the following polymers belong to the class of formaldehyde resin?

4. Pick out the wrong statement

5. Which of the following polymers has the tendency of decomposing before melting?

6. Which of the following is the most important rubber compounding ingredient which is used to improve wearing qualities of both natural rubber & SBR by imparting toughness?

7. Ion exchange resins are made of

8. Plastic tubes & pipes are generally made by molding

9. Most of the plastics are safe to be used up to a maximum temperature of _______ C

Mechanical Operation

1. A tube mill compared to a ball mill

2. __________ mixer is used for devulcanisation of rubber scrap & making water dispersion & rubber solution

3. Screen capacity is not a function of

4. Grindabilit of a material does not depend upon its

5. Rittinger’s number designates the new surface created per unit mechanical energy absorbed by the material being crushed. A larger value of Rittinger’s number of a material indicates its

6. Where the density difference of the two liquid phases to be separated is very small (as in milk cream separator), the most suitable separator is a

7. Basic slag is not ground in

8. Shape factor for a cylinder whose length equals its diameter is

9. Which of the following mechanical conveyors does not come under the division ‘carriers’?

10. In case of a hammer crusher, the

Petroleum Refinery Engineering

1. Feedstock for the production of biodiesel is

2. The first crude oil refinery of India is located at

3. Which of the following constituents present in petroleum is responsible for ash formation?

4. Octane number of gasoline produced by the two-stage fluidized catalytic cracking process is

5. A typical yield of diesel in the straight run distillation of crude oil may be about percent

6. Pick out the wrong statement

7. Pick out the wrong statement

8. Which one is used to determining the color of petroleum products?

9. Olefins are

10. Illuminating characteristics of kerosene is expressed by its

Process Control And Instrumentation

1. The term analogous to the electrical current in a thermal system is the

2. Which of the following is a ‘contact’ pyrometer?

3. A mercury barometer measures the ___________ pressure

4. Starting temperature of optical radiation pyrometer is __________.

5. Pressure of 0.0001 absolute psi can be measured by gauge

6. The response of two tanks of the same size and resistance in series is

7. The temperature range for which copper resistance thermometer can be used is ________ C

8. Continuous measurement of moisture in paper is done by

9. An amplitude ratio of 0.1 corresponds to ______________ decibels

10. The amplitude ratio for the sinusoidal response of _______________ is < 1

Materials And Construction

1. ________ possesses viscoelastic properties

2. Caustic soda is produced in a mercury cell having anode and cathode made respectively of moving mercury and

3. Brass is an alloy of

4. Slow and progressive deformation of a material with time under constant stress is called

5. Acetaldehyde is produced by hydration of acetylene in a sulphuric acid solution of mercuric sulfate. Hydration tower is made of

6. Babbit metals used for making bearings are

7. Which of the following materials may prove unsuitable for handling acetic acid (glacial & anhydrous) at 40°C?

8. Cast iron has

9. Steel tower used for the storage of oleum

10. Which of the following has the highest compressive strength?

Chemical Engineering Plant Economics

1. Effluent treatment cost in a chemical plant is categorized as the _________ cost

2. A shareholder has __________ say iii the affairs of company management compared to a debenture holder

3. Pick out the wrong statement

4. Which of the following does not come under the sales expenses for a product of a chemical plant?

5. A machine has an initial value of Rs. 5000, service life of 5 years, and a final salvage value of Rs. 1000. The annual depreciation cost by straight-line method is

6. Following the six-tenth factor rule, if a log-log plot of the capacity of the equipment vs. cost of the equipment is made, then a straight line is obtained, whose slope is equal to

7. An annuity is a series of equal payments occurring at equal time intervals, and this amount includes the sum of all payments plus interest if allowed to accumulate at a definite rate of interest from the time of initial payment to the end of the annuity term. An ordinary annuity is used in the calculation of the 

8. A series of equal payments (e.g., deposit or cost) made at equal intervals of time is known as

9. Which of the following methods of depreciation calculations results in book values greater than those obtained with the straight-line method?

10. Total product cost of a chemical plant does not include the __________ cost

Environmental Engineering

1. Iron & manganese present in the polluted water is removed by

2. Presence of bacteria in potable (drinking) water causes

3. Which is the most practical and economical method for the removal of suspended solid matter from polluted water?

4. The amount of chemical coagulant added for treatment of polluted water ________ with an increase in temperature of the polluted water to be treated 

5. Pick out the %Tong statement

6. Maximum permissible turbidity in potable water is _______ ppm

7. A shallow pond in which the sewage is retained and biologically treated is called

8. Ambient noise level can be reduced by _______ decibels by planting trees like coconut, neem, etc.) near public utilities buildings (like hospitals & schools)

9. Atmospheric pollution caused by the exhaust gas of supersonic transport air-crafts is mostly in the atmospheric region called

10. Thermal pollution of water increases its toxicity and oxidation of oxygen demanding waste besides favoring bacterial growth. A rise in water temperature by 10°C, doubles the toxic effects of _________ present in it

Nuclear Power Engineering

1. Main source of _______________ is monazite sand

2. The half-life period of a radioactive substance is best determined by counting the number of alpha particles emitted per second in a Geiger Muller counter from its known quantity. If the half-life period of a radioactive substance is one month, then

3. A fast breeder reactor employs

4. Enrichment of uranium is done to increase the concentration of ----- in the natural uranium

5. Fuel for a nuclear reactor (thermal) is

6. Graphite is used in nuclear reactors as

7. Which one is radioactive in nature?

8. Uranium ore is currently mined & concentrated at

9. Percentage of U-238 in natural uranium is around

10. The most commonly used nuclear fuel in boiling water reactors is

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