Category: Engineering Chemistry Objective Questions

Engineering Chemistry Multiple Choice Questions on “Uses and Limitations of Phase Rule”.

1. For the T-C relation in phenol, there happens a regular sharpening in concentration of phenol. What will happen if the equilibrium conditions are varied at a particular point?
a) The curve remains unchanged
b) The curve decreases
c) The curve increases
d) The curve inverts
Answer: c
Clarification: We know that both the equilibrium points are achieved at the same concentration and hence there is a regular increase. If the equilibrium conditions are varied, then the steadiness vanishes and hence the curve will show an abnormal increase in its concentration.

2. In the general phase diagram of Ferric chloride – water system, what causes reduction in water content in ferric chloride at each step?
a) Reduction in moisture content
b) Reduction in concentration
c) Reduction in equilibrium shift
d) Increase in temperature
Answer: a
Clarification: Since for each transition from one phase to another for a component, the moisture content decreases due to increase in temperature. Hence the water concentration in ferric chloride decreases as the temperature increases.

3. The mechanism of diffusion of small atomic radius compared to the parent material would be described by __________________
a) Substitutional diffusion
b) Interstitial diffusion
c) Vacancy diffusion
d) Drift
Answer: b
Clarification: During equilibrium process, metastable curve appears and due to variation in equilibrium composition, the curve disappears. To fix this equilibrium back to form, there takes place diffusion between interstitial atoms called interstitial diffusion.

4. What happens during a non-steady state diffusion?
a) The composition behavior does not change with time
b) The composition behavior changes with time
c) The diffusion can be described by Mond’s Second Law
d) Zero composition
Answer: d
Clarification: Only during a steady state reaction (invariant reaction), the composite and other parameters like concentration, temperature, pressure, solubility etc can be determined. Hence under non- equilibrium conditions, all the above parameters are negligible and hence there is zero composition.

5. The driving force of the diffusion process in phase diagram is __________________
a) The slope in Gibbs free energy
b) The slope in solubility
c) The slope in temperature
d) The slope in pressure
Answer: a
Clarification: Since the driving force (parameter defining force) is determined only by a small change in chemical composition with respect to temperature, the slope in the chemical composition will determine the driving force.

6. In the mixture of propanol and iso propanol, identify the component at the meeting point of these two components.
a) Propanol
b) Propane
c) Propane-2-ol
d) Water
Answer: c
Clarification: When two different components are made to show phase relation, together, then the component which is formed at the eutectic region is a mixture of their metastable components. Thus here it is Propane-2-ol.

7. What are the limits of phase rule?
a) Cannot determine the presence of more the one phase in a system
b) Cannot determine solubility
c) Cannot determine composition
d) Can determine temperature
Answer: a
Clarification: Since phase rule focusses only on one equilibrium state of the system, the presence of even tiny traces of multiple phases cannot be identified using phase rule which is the main drawback of this rule. This drawback is solved by Lever rule.

8. In the mixture of liquid and vapor compositions, identify the type of component present in between the two components (at equilibrium point).
a) Regular solution
b) Equilibrium solution
c) Transition solution
d) Steady state solution
Answer: d
Clarification: Since phase rule cannot determine multiple phases in a single system, regular solution is not obtained. Similarly, equilibrium solution is also not obtained (according to Weiss law). Thus a steady solution is obtained.

9. Calculate the concentration from the given data.
T = 20 degrees
P = 2 atm
a) 5
b) 2
c) 10
d) 0
Answer: c
Clarification: According to Weiss law (which suits only for phase components), concentration is given by temperature/pressure. Thus in this case, concentration is equal to 20/2=10.

10. What is the efficiency of phase rule over Lever rule?
a) 25%
b) 50%
c) 75%
d) 85%
Answer: d
Clarification: Since, phase rule works only under equilibrium conditions and also only a few parameters like composition, solubility, temperature can be determined, it has limitations over lever rule. Another point is it fails to explain the T-C relation.

Engineering Chemistry Questions and Answers for Freshers focuses on “Elastomers – 2”.

1. Which of the following act as a catalyst in the preparation of Buna-S?
a) Benzoyl peroxide
b) Hydrogen peroxide
c) Cumene hydroperoxide
d) Acrylonitrile
Answer: c
Clarification: Cumene hydroperoxide act as a catalyst in the preparation of Buna-S (Butadiene styrene).

2. Which of the following statement is incorrect about the SBR?
a) It has low load bearing capacity
b) It has high abrasion resistance
c) It swells in oils and solvents
d) It has low oxidation resistance
Answer: a
Clarification: SBR has high load bearing capacity, high abrasion resistance, swells in oil and solvent and has low oxidation resistance.

3. Which of the following is an application of SBR?
a) Conveyor belts for food
b) Lining of tanks
c) Oil-resistance foam
d) Printing rollers
Answer: b
Clarification: Lining of tanks, adhesives, gaskets, motor tyres, etc are some of the applications of SBR.

4. Buna-N is prepared by co-polymerisation of butadiene and acrylonitrile in the emulsion system.
a) True
b) False
Answer: a
Clarification: Buna-N is prepared by the co-polymerisation of butadiene and acrylonitrile in the emulsion system. Buna-N is nitrile rubber used in the automotive and aeronautical industry to make fuel and oil handling hoses.

5. Which of the following has the best resistance to oils?
a) Natural rubber
b) Neoprene
c) Nitrile rubber
d) Styrene rubber
Answer: c
Clarification: Nitrile rubber has the best resistance to oils among the following options. All the other options have lower resistance to oils.

6. Which of the following is not an application of neoprene?
a) Conveyor belts
b) Wire and cable insulation
c) Adhesives
d) Printing rollers
Answer: d
Clarification: Conveyor belts, adhesives, wire and cable insulation, shoe-soles, etc are some of the applications of neoprene. Printing rollers is not an application of neoprene.

7. The major constituent of butyl rubber is ____________
a) Isobutylene
b) Isoprene
c) Chloroprene
d) Acrylonitrile
Answer: a
Clarification: In butyl rubber, isobutylene constitutes (95-99) % and isoprene constitutes (1-5) %.

8. Which of the following act as a catalyst in the preparation of butyl rubber?
a) Cumene hydroperoxide
b) Anhydrous AlCl₃
c) Lewis base
d) Grignard reagent
Answer: b
Clarification: Anhydrous AlCl₃ acts as a catalyst in the preparation of butyl rubber. Butyl rubber is a synthetic rubber, a co-polymer of isobutylene with isoprene.

9. The solvent used in the preparation of butyl rubber is ____________
a) Methyl iodide
b) Methyl halide
c) Methyl chloride
d) Methyl sulphide
Answer: c
Clarification: The solvent used in the preparation of butyl rubber is methyl chloride. Butyl rubber is a synthetic rubber, a copolymer of isobutylene with isoprene.

10. Because of its hydrocarbon nature, butyl rubber is soluble in hydrocarbon solvents but has excellent resistance to polar solvents like alcohol and acetone.
a) True
b) False
Answer: a
Clarification: Because of its hydrocarbon nature, butyl rubber is soluble in hydrocarbon solvents but has excellent resistance to polar solvents like alcohol and acetone. Butyl rubber and halogenated rubber are used for the inner liner that holds the air in the tire.

areas of Engineering Chemistry for Freshers,

Engineering Chemistry Multiple Choice Questions on “Solid Fuels – 1”.

1. Which of the following fuel is formed from industrial waste?
a) Lignite
b) Briquetted fuel
c) Spent tan
d) Rice husk
Answer: c
Clarification: Spent tan is a nuclear fuel that has been irradiated in a nuclear reactor. Rice husk is obtained from animal waste and briquetted fuel is compressed block of coal dust.

2. Which of the following industrial waste gas is used in creating jet fuel?
a) Nitrogen di oxide
b) Carbon monoxide
c) Sulphur di oxide
d) Hydrogen di sulphide
Answer: b
Clarification: Carbon monoxide is fermented through gas fermentation which forms alcohols and then these alcohols formed are converted into jet fuel by the process of dehydration and hydrogenation.

3. Which of the following is a renewable energy resource?
a) Coal
b) Cow dunk
c) Charcoal
d) Wood
Answer: d
Clarification: Wood is obtained from trees and trees can be replanted easily, so the are renewable form of energy. Examples of wood-pine, cedar etc.

4. From which alcohol does softwood lignin is derived?
a) Coniferyl alcohol
b) Sinapyl alcohol
c) Ethyl alcohol
d) 4, 3 tri butyl alcohol
Answer: a
Clarification: Coniferyl alcohol is a phytochemical which is used as an intermediate in biosynthesis of eugenol. Sinapyl and Coniferyl alcohol can also be used in deriving hardwood lignin.

5. Which of the following fuel is preferred for space heating?
a) Coal tar
b) Diesel
c) Hydrogen gas fuel
d) Wood
Answer: d
Clarification: Wood has high flame emissivity (ratio of the energy radiated from a materials surface to the energy radiated from black body at same temperature and wavelength) due to which it is used in space heating.

6. By which process does the wood charcoal is obtained?
a) Destructive distillation
b) Steam distillation
c) Vacuum distillation
d) Simple distillation
Answer: a
Clarification: In destructive distillation the decomposition of the feedstock of wood is done by heating at high temperature. The wood charcoal so obtained is of good quality.

7. Which of the following does require wood charcoal for its production?
a) Steel alloys
b) Activated carbon
c) Alloys of tin
d) Plaster of Paris
Answer: b
Clarification: Activated carbon finds extensive applications for decolourisation, adsorption of gases and vapours and recovery of solvents from gases and air.

8. Which type of coal is generated by the action of fungi and bacteria?
a) Peat
b) Bituminous
c) Lignite
d) Anthracite
Answer: a
Clarification: It is considered as the first stage of conversion of vegetable debris into coal under water logged conditions by the action of fungi and bacteria. Peat is generally found in high altitude.

9. Which of the following country consist of the largest peat deposit?
a) India
b) Canada
c) USA
d) Russia
Answer: d
Clarification: Russia contains 42% of world’s peat deposits. Ireland also have a large peat content around 16.2 %.

10. Which of the following content does upland type of peat consist?
a) Leaves
b) Twigs
c) Decomposed heaths and mosses
d) Sedges and grasses
Answer: c
Clarification: Upland peat is at the top of the peat which only consists of dead material which are decomposed heaths and mosses.

11. What happens when we carbonise peat?
a) Charcoal is produced
b) Coke is produced
c) Peat is converted into lignite
d) Peat is converted into bituminous
Answer: b
Clarification: Under proper conditions of temperature and pressure if we carbonise peat then coke and gas is produced. But at low temperatures chars, oils and light spirit are formed.

12. For what purpose does the dried peat is used?
a) Thermal insulation
b) Liquid purification
c) Destructive distillation
d) For production of calcium carbide
Answer: a
Clarification: Thermal insulation is the reduction of heat transfer between objects in the range of radiative influence. Dried peat is also used as fuel for steam raising and gas purification.

13. How much moisture content is present in lignite?
a) 60-75%
b) 10-25%
c) 35-50%
d) 75-100%
Answer: c
Clarification: Lignite moisture can be brought down to a level of 10-15%. Peat can contains 90% moisture in it.

14. From which of the mining technique lignite can be extracted?
a) Open cast mining
b) High wall mining
c) Drift mining
d) Slope mining
Answer: a
Clarification: Open cast mining is used when deposits of commercially used minerals are near the surface of the earth. It is a type of surface process.

15. Which of the following coal have highest volatile matter?
a) Peat
b) Lignite
c) Bituminous
d) Anthracite
Answer: b
Clarification: Lignite burns with long smoky flame which states that it contains high volatile matter. Lignite absorbs oxygen readily on exposure to air.

Engineering Chemistry Multiple Choice Questions on “Cracking – 2”.

1. How can we increase the ageing of alumina-silica catalyst?
a) By making the contact of catalyst with heavy metals
b) By making the contact of catalyst with lighter metals
c) By making the contact of catalyst with heavy non-metals
d) By making the contact of catalyst with lighter non-metals
Answer: b
Clarification: The process of ageing can be accelerated, if the catalyst comes into the contact with compounds containing sulphur, vanadium, nickel etc. The ageing can also be increased if the conditions are more rigid.

2. How can we regenerate alumina-silica catalyst?
a) By increasing the particles of coke on the catalyst
b) By increasing the amount of catalyst
c) By decreasing the particles of coke on the catalyst
d) By making it react with suitable anion or cation
Answer: c
Clarification: The catalyst can be regenerated to store their activity and reactivity by burning of the coke deposited on the catalyst particles. The catalyst used in the catalytic reactions are very expensive, due to which their regeneration is necessary.

3. What happens when the crude petroleum fractions are made in contact of catalyst in cracking process?
a) Solid substances are obtained
b) Liquid substances are obtained
c) Gaseous substances are obtained
d) Solid, liquid and gaseous substances are obtained
Answer: d
Clarification: Gases, gasoline, coke and other liquid products are formed when a catalyst comes in contact with crude petroleum fractions in cracking process. This happens due to the various reactions such as dehydrogenation, isomerization etc.

4. Catalytic cracking process are more expensive to run than the thermal cracking process.
a) True
b) False
Answer: a
Clarification: The catalyst used in these processes are expensive. This type of cracking gives more stable and superior product. The yields obtained by this type of cracking are higher.

5. Which compounds can be obtained from higher percentile yields of butyne-butylene fractions?
a) Gasoline
b) Coke
c) Super-Gasoline
d) Diesel
Answer: c
Clarification: The octane ratings of gasoline fuel is 87 where as the octane ratings of super-gasoline is 93. These fuels are more suitable than gasoline fuels.

6. In which form does the catalyst are used in fluid-bed cracking?
a) In the form of oxides
b) In the form of vapours
c) Liquid form
d) In the form of fine powder
Answer: d
Clarification: In this process, the catalyst in the form of fine powder is circulated through the cracking reactor with the help of oil vapours. The catalyst accelerates and directs the cracking and also acts as a heat transfer medium.

7. In which process does the oil vapours are heated to their cracking temperatures?
a) Thermal cracking
b) Fixed-bed cracking
c) Fluid-bed cracking
d) Coking
Answer: b
Clarification: In fixed-bed cracking the oil vapours are heated to their cracking temperatures and are passed on to the fixed catalyst bed. When the catalyst gets carbonised, it is reactivated by burning off the carbon deposited.

8. At what temperature does the oil is vaporised and heated in fixed-bed cracking process?
a) 400-500^oC
b) 700-800 ^oC
c) 100-200 ^oC
d) More than 1000 ^oC
Answer: a
Clarification: The heavy oil charge is passed through a heater, where the oil is vaporised and heated to 400-500 ^oC. The hot vapours are then passed over fixed bed catalyst. The pressure is about 1-5 kg/cm².

9. How much percentile of low molecular weight hydrocarbons are formed in fixed-bed catalytic cracking?
a) 15-20 %
b) 50-60 %
c) 30-40 %
d) 0-5 %
Answer: c
Clarification: About 30-40 % of the charge is converted into low molecular weight hydrocarbons, conforming the composition of catalyst. About 4 % of carbon is formed during this process.

10. What happens to the heavy gas oil fractions in the cracking process?
a) It escapes out
b) Condensed at the bottom of the column
c) It gets dissolved in the solution
d) It blocks the air holes
Answer: b
Clarification: The cracked vapours of the oil enters the fractionating column where the gasoline vapours and other gaseous products are recovered from the top, while the heavy gas oil fractions are condensed at the bottom of the column.

11. What happens in the stabilizer of fixed-bed catalytic cracking?
a) Coke is obtained in it
b) Coal gas is formed in it
c) Butane is formed
d) Gasoline is recovered
Answer: d
Clarification: The condensed vapours of the catalytic system are send to the stabilizer, where the dissolved gases are removed and gasoline is recovered. The light gases produced in cracking are no longer allowed to escape into the air.

12. Which type of raw materials are formed from the light gases produced by cracking?
a) Synthetic rubber
b) Freezing agents
c) Acids
d) Inorganic compounds
Answer: a
Clarification: These light gases form valuable raw materials for the synthesis of new types of fuel. The other materials such as antifreeze, plastics and synthetic rubber are obtained from these gases.

13. Which of the following is the main disadvantage of hydrogenation cracking?
a) It cannot achieve complete cracking
b) It creates holes in the reactor
c) It is expensive and intricate
d) It requires more human effort
Answer: c
Clarification: In hydrogenation cracking, the heavy oil is cracked in the presence of hydrogen under high temperature and pressure. Complete cracking can be achieved by recycling.

14. In fluid-bed catalytic cracking, cracking takes place on ___________________
a) The side walls of the turbulent
b) The surface of the turbulent
c) Upper portion of the turbulent
d) Instruments of the turbulent
Answer: b
Clarification: Cracking takes place on the surface of the turbulent catalyst bed as it circulates with the oil vapours in the reactor at a temperature of 530 ^oC and at a pressure of about 3 to 5 kg/cm².

15. Fluid-bed catalytic cracking products contain high proportions of aromatic and iso-paraffin compounds than thermal cracking process.
a) True
b) False
Answer: a
Clarification: The products obtained in fluid-bed catalytic cracking are distributed in different chambers due to which it has higher proportions of aromatic and iso-paraffin compounds than thermal cracking. This process is used by the industries for the cracking process.

Engineering Chemistry Multiple Choice Questions on “Lime Soda Process”.

1. What is the molecular formula of lime?
a) CaCO₃
b) Al(OH)₃
c) Ca(OH)₂
d) Mg(OH)₂
Answer: c
Clarification: The molecular formula of lime is Ca(OH) ₂. It is a white caustic alkaline substance consisting of calcium oxide, which is obtained by heating limestone and which combines with water with the production of much heat.

2. What is the molecular formula of soda?
a) Na₂CO₃
b) Al₂(SO₄)₃
c) Mg(OH) ₂
d) Ca(OH) ₂
Answer: a
Clarification: The molecular formula of soda is Na₂CO₃. It is also called washing soda or soda ash.

3. Which of the following is not a precipitate in lime-soda process?
a) CaCO₃
b) Fe(OH) ₃
c) Al(OH) ₃
d) Al₂(SO₄)₃
Answer: d
Clarification: Al₂(SO₄)₃ is not a precipitate in lime-soda process. All the other options are the precipitate in lime-soda process.

4. Which of the following is not used as a coagulant in lime-soda process?
a) Alum
b) Calcium bicarbonate
c) Aluminium sulphate
d) Sodium aluminate
Answer: b
Clarification: Calcium bicarbonate is not used as a coagulant in lime-soda process. Alum, aluminium sulphate and sodium aluminate are used as coagulants in lime-soda process.

5. What is the function of coagulant?
a) It helps in the formation of fine precipitate
b) It helps in the formation of coarse precipitate
c) It helps in increasing the solubility
d) It helps in increasing the boiling point
Answer: b
Clarification: Coagulants helps in the formation of coarse precipitate. C?oagulation is a process of addition of coagulant to destabilize a stabilized charged particle.

6. For the softening of one mole of magnesium bicarbonate, the number of mole of lime required is?
a) 2
b) 3
c) 4
d) 5
Answer: a
Clarification: For the softening of one mole of magnesium bicarbonate, the number of mole of lime required is two. The ratio of bicarbonate to lime in lime-soda process is 1:2.

7. The residual hardness in lime-soda process is ___________
a) 0-2 ppm
b) 5-15 ppm
c) 15-50 ppm
d) 50-70 ppm
Answer: c
Clarification: The residual hardness in lime-soda process is 15-50 ppm. Lime soda softening cannot produce a water at completely free of hardness because of the low solubility of CaCO₃ and Mg(OH)₂.

8. In lime soda process, capital cost is ___________ whereas operational expenses are __________
a) High, low
b) High, high
c) Low, low
d) Low, high
Answer: d
Clarification: In lime soda process, capital cost is low whereas operational expenses are high. It is because the chemicals and reagents used are costly.

9. In lime-soda process, no exchange of ions occurs.
a) True
b) False
Answer: a
Clarification: In lime-soda process, no exchange of ions occurs. Recarbonation is used to stabilize the water. The excess lime and magnesium hydroxide are stabilized by adding carbon dioxide, which also reduces the pH from 10.8 to 9.5.

10. Which of the following is the second step for calculating the amount of lime and soda?
a) Identification of lime and soda for different salts
b) Calculation of CaCO₃ equivalents
c) Calculation of lime requirements
d) Calculation of soda requirements
Answer: b
Clarification: Calculation of CaCO₃ equivalents is the second step for calculating the amount of lime and soda. First step is to identify the lime and soda for different salts. and the last two steps are the calculation of lime and soda requirements.

Engineering Chemistry Multiple Choice Questions on “Characteristics of Electroplating Wastes”.

1. Under what condition will impurities form under cathode?
a) When temperature exceeds critical temperature
b) When pressure exceeds critical pressure
c) When the amount of electrolyte is increased enormously
d) When water content is increased
Answer: b
Clarification: Since during electroplating, the standard critical temperature and pressure are maintained. If the temperature is increased, then only the polarities of the electrode change, but if the pressure is increased, the impurities will shift from anode to cathode.

2. Which of the following is not the characteristic of impurities in electroplating?
a) Are formed near cathode
b) Are mostly noble metals
c) Are formed near anode
d) Increase the strength of solution
Answer: a
Clarification: During electroplating, the impurities are mostly noble metals (especially in the case of alkali and alkaline earth metals). That is why due to higher density at anode, the impurities are formed near anode.

3. What causes an increase in the amount of formation of impurities at a higher rate?
a) Increase in concentration
b) Decrease in concentration
c) Deterioration in the amount of molecules
d) Destruction in the electrode
Answer: c
Clarification: During electroplating process, the amount of molecules plays an important role in the determination of electrolysis of absorbent (water or any other fluid). Thus decrease in the amount of molecules will increase the formation of impurities.

4. Determine the coefficient of relative constant from the following data.
Alpha = 23
C = 43 g
T = 100 K
a) 10
b) 7
c) 9.89
d) 8
Answer: c
Clarification: We know that the relative constant can be calculated from the formula: C/T X alpha. Therefore from the given data, we can calculate the constant as 43/100×23 = 9.89.

5. Determine the coefficient of the relative constant from the following data.
Alpha = 1
C = 3 g
T = 10 K
a) 2
b) 0
c) 1
d) 0.3
Answer: d
Clarification: We know that the relative constant can be calculated from the formula: C/T X alpha. Therefore from the given data, we can calculate the constant as 3/100×1=0.3.

6. What will be the observation when the electrolyte concentration is increased to double times the previous concentration?
a) The Composition increases 4 times
b) The composition increases 2 times
c) The composition increases 8 times
d) The composition does not change
Answer: d
Clarification: Since during electroplating the concentration of the electrolyte is independent of external factors like temperature of the system, pressure and specific gravity, it does not have anything to do with composition.

7. Determine the curational capacity of zinc aluminium from the following.
a) Noblular transmission
b) Isotropic mass activation
c) Semi concentric circulation
d) Isobaric transmission
Answer: b
Clarification: During electroplating process, the contents like concentration, composition, electronic configuration of molecules are purely based on the ingenious capacity of electrolysis process, the curational capacity is isotropic in nature.

8. Calculate the electron concentration.
Alpha: 34
C = 3
T = 23 K
a) 11.3
b) 23
c) 8
d) 0
Answer: a
Clarification: We know that the electron concentration is given by the formula concentration/alpha value. Therefore in this problem, from the given data, we have the value of electron concentration as 34/3=11.3.

9. Calculate the value of alpha from the following.
Electron concentration: 4
C=2
a) 0
b) 8
c) 2
d) 1
Answer: b
Clarification: We know that the electron concentration is given by the formula concentration/alpha value. Therefore alpha = electron concentration x C. Therefore in this problem, from the given data, we have the value of alpha as 4×2=8.

10. The emulsified impurities are found near ____________
a) Cathode
b) Anode
c) Nowhere
d) At electrolyte site
Answer: a
Clarification: Since during the process of electroplating, the higher density molecules adhere to the anode and lower density molecules adhere to cathode. Since emulsified impurities are low density molecules, they stick towards cathode.