Category: Engineering Chemistry Objective Questions

Engineering Chemistry Multiple Choice Questions on “Faraday’s Laws of Electrolysis”.

1. According to Faraday’s first law of electrolysis, the amount of any substance deposited at the electrode is directly proportional to the quantity of _______________
a) Voltage drop
b) Resistance
c) Electricity passed
d) Tolerance
Answer: c
Clarification: According to Faraday’s law of electrolysis, the amount of any substance deposited at the electrode is directly proportional to the quantity of electricity passed. It is given by:
m = (Q / F) * (M / Z)
where, m = Mass of the substance liberated at an electrode in grams
Q = Total electric charge passed through the substance in Coulombs
F = Faraday constant
M = Molar mass of the substance in grams per mol
Z = Valency number of ions of the substance
For Faraday’s first law, M, F, and z are constants, so that the larger the value of Q the larger m will be.

2. Electrochemical equivalent may be defined as the ____________ of the substance deposited by the passage of 1 coulomb of electricity.
a) Volume
b) Weight
c) Density
d) Velocity
Answer: b
Clarification: Electrochemical equivalent may be defined as the weight of the substance deposited by the passage of 1 coulomb of electricity. The electrochemical equivalent of an element is measured with a voltameter.

3. 1 Faraday = _______________
a) 1 coulomb
b) 1000 coulomb
c) 5000 coulomb
d) 96500 coulomb
Answer: d
Clarification: 1 Faraday = 96,500 Coulomb. It is calculated mathematically and is widely used everywhere.

4. According to Faraday’s second law, the weights of different substances evolved by the passage of the same quantity of electricity are proportional to their _______________
a) Chemical equivalent weight
b) Current supply
c) Chemical equivalent density
d) Volume
Answer: a
Clarification: According to Faraday’s second law, the weights of different substances evolved by the passage of same quantity of electricity are proportional to their chemical equivalent weights. For Faraday’s second law, Q, F, and z are constants, so that the larger the value of M/z (equivalent weight) the larger m will be.

5. Silver is electrodeposited on a metallic vessel of surface area 800 cm² by passing a current of 0.2 A for 3 hours. The thickness of silver deposited is ____________
a) 0.1 mm
b) 0.02 mm
c) 0.05 mm
d) 0.2 mm
Answer: b
Clarification: The thickness of silver deposited is 0.0288 mm. It is calculated mathematically.

6. The velocity with which an ion moves under a potential gradient of __________ volt/cm in a solution is called ionic mobility.
a) 5
b) 4
c) 3
d) 1
Answer: d
Clarification: The velocity with which an ion moves under a potential gradient of one volt/cm in a solution is called ionic mobility. The separation of ions according to their mobility in the gas phase is called ion mobility spectrometry, in liquid phase, it is called electrophoresis.

7. The unit of ionic mobility in SI system is ____________
a) msV^-1
b) m³sV²
c) m²s^-1V^-1
d) m²s^-1V
Answer: c
Clarification: The unit of ionic mobility in SI system is m²s^-1V^-1. The separation of ions according to their mobility in gas phase is called ion mobility spectrometry, in liquid phase it is called electrophoresis.

8. Which of the following factor does not affect ionic mobility?
a) Pressure
b) Nature of ions
c) Temperature
d) Concentration of the solution
Answer: a
Clarification: The factors which affect the ionic mobility are- nature of the ions, concentration of the solution, temperature and the applied potential difference. It does not get affected by pressure.

9. Faraday constant is the amount of electricity present in 100 moles of electrons.
a) True
b) False
Answer: b
Clarification: Faraday constant is the amount of electricity present in 1 mole of electrons. It is equal to 96500 C mol^-1.

10. The molecular formula of cryolite is ____________
a) Al₂O₃
b) Fe₂O₃
c) Na₃AlF₆
d) Na₃MgI₆
Answer: c
Clarification: The molecular formula of cryolite is Na₃AlF₆. Cryolite is used as an insecticide and a pesticide. It is also used to give fireworks a yellow color.

11. Refined bauxite is dissolved in molten cryolite at a temperature slightly below ____________
a) 0⁰C
b) 100⁰C
c) 2000⁰C
d) 1000⁰C
Answer: d
Clarification: Refined bauxite is dissolved in molten cryolite at a temperature slightly below 1000⁰C. Cryolite is used as an insecticide and a pesticide. It is also used to give fireworks a yellow color.

12. Aluminium and its alloys can be given shapes of pipes, tubes, rods, wires, plates or foils.
a) True
b) False
Answer: a
Clarification: Aluminium and its alloys can be given shapes of pipes, tubes, rods, wires, plates or foils. Aluminium is one of the most widely used element. The main alloying agents of aluminium are copper, zinc, magnesium, manganese, and silicon

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

1. What is the colloidal mixture of solid with solid called?
a) Solid sol
b) Liquid sol
c) Sol
d) Gel
Answer: a
Clarification: Since in this colloidal mixture, a solid is mixed with another solid, the molecules are having a tight bond between them. Hence it is called solid sol.

2. What is the colloidal solution of liquid with solid called?
a) Sol
b) Gel
c) Foam
d) Form
Answer: a
Clarification: In the colloidal mixture of solid and liquid which is called sol, the bond is not as strong as compared to solid sol. The bond is lightly less bonded. Hence the name sol.

3. What is a colloidal solution of liquid in liquid called?
a) Foam
b) Form
c) Emulsification
d) Solid sol
Answer: c
Clarification: Since we know that the molecular bond between the liquid and liquid is not that much strong and hence will sometimes form stable solutions (may be homo or heterogeneous).

4. What is the colloidal solution of liquid and gas called?
a) Aerosol
b) Gel
c) Sol
d) Emulsion
Answer: a
Clarification: We know that out of all other bonds, the weakest bond is between a gaseous molecule and a gaseous molecule. The next weakest bond after this is between a liquid and a gaseous molecule. Such a colloid is called an aerosol.

5. Which of the following colloidal combinations is not possible?
a) Liquid in solid
b) Solid in liquid
c) Gas in gas
d) Gas in solid
Answer: c
Clarification: We know that gases are completely miscible in nature. Hence n number of gases together will be considered only as a single molecule. Hence such a colloidal combination is not possible.

6. Identify the liquid-liquid emulsion from the following.
a) Milk
b) Oil
c) Salt water
d) Sugar solution
Answer: a
Clarification: We know that milk is a combination of many materials like vitamins, minerals, fats etc and hence forms a colloidal solution. Since these materials are so microscopic and are dispersed in a liquid, milk is an example of an emulsion.

7. Identify a sol from the following.
a) Stone
b) Paint
c) Ink
d) Rice milk
Answer: b
Clarification: Paint is thicker as compared to other liquid fluids. It’s hardness scale is assumed to be 9 on the Mohr’s scale which is next to kerosene. Hence paint is considered to a solid liquid sol.

8. Identify a gel from the following.
a) Curd
b) Cheese
c) Yogurt
d) Yolk
Answer: a
Clarification: Curd is got after processing from milk. It is considered to have a stronger bond than cheese and weaker bond than milk. Hence it is considered to be a liquid solid gel.

9. Identify the foam from the following.
a) Bubbles
b) Cake
c) Froths of air
d) Soap
Answer: c
Clarification: We know that froths of air are similar to bubbles but they have more moisture content in them as compared to bubbles. The composition of froths is nothing but a mixture of water and moisture. Hence it is gas-liquid foam.

10. Identify the form from the following.
a) Cheese
b) Paint
c) Pumice stone
d) Cork
Answer: c
Clarification: According to the hardness scale, it is found that pumice stone is stronger than lime stone but is weaker than quartz. Hence it is a colloid of solid and a gas (moisture). So, it is a form.

Engineering Chemistry Multiple Choice Questions on “R, S- Configuration and Water Softening”.

1. Which of the following is not a priority rule for R, S-Configuration?
a) If the four atoms attached to the chiral centre are all different, priority depends on atomic number, with the atom of lower atomic numbers getting lower priority
b) If the two atoms attached to chiral centre are same, the atoms attached to each of these first atoms are compared
c) When there is a double bond or triple bond, both atoms are considered to be duplicated or triplicated
d) If the four atoms attached to the chiral centre are all different, priority depends on atomic number, with the atom of higher atomic numbers getting lower priority
Answer: d
Clarification: If the four atoms attached to the chiral centre are all different, priority depends on atomic number, with the atom of lower atomic numbers getting lower priority.

2. If our eyes travel in counter clockwise direction from the ligand of highest priority to the ligand of lowest priority, the configuration is ____________
a) R-Configuration
b) S-Configuration
c) E-Configuration
d) C-Configuration
Answer: b
Clarification: In S-Configuration, our eyes travel in counter clockwise direction from the ligand of highest priority to the ligand of lowest priority.

3. According to the selection rules, the decreasing order of preference is __________
a) –NH₂ > -C₆H₅ > -CH(CH₃)² > -H
b) –CH(CH₃)² > -C₆H₅ > -H> -NH₂
c) –NH₂ > -CH(CH₃)² > -C₆H₅ > -H
d) -C₆H₅ > -CH(CH₃)² >–NH₂ > -H
Answer: a
Clarification: The atom of higher atomic numbers gets higher priority. So, –NH₂ group has the highest priority of all.

4. The process of removal of hardness of water, irrespective of whether it is temporary or permanent is termed as __________
a) Cleansing action of water
b) Hardness of water
c) Softening of water
d) Purity of water
Answer: c
Clarification: The process of removal of hardness of water, irrespective of whether it is temporary or permanent is termed as softening of water. This process includes both temporary as well as permanent hardness.

5. The external treatment of water does not include __________
a) Lime-soda process
b) Sequestration
c) Zeolites
d) Ion-exchange process
Answer: b
Clarification: The external treatments of water include lime-soda, zeolites and ion-exchange processes. It does not include sequestration.

6. Which of the following conditioning method is not used in internal treatment?
a) Colloidal
b) Calgon
c) Carbonate
d) Bicarbonate
Answer: d
Clarification: Colloidal, calgon, phosphate and carbonate conditioning methods are used in internal treatment. Bicarbonate is not used for this purpose.

7. Select the incorrect statement from the following option.
a) Internal treatment is carried out outside the boiler before water enters into the boiler
b) Internal treatment methods are followed by blow-down operations
c) Internal treatment is required in low pressure boilers
d) Internal treatment is a corrective method
Answer: a
Clarification: Internal treatment is carried out inside the boiler. All the other options are correct.

8. External treatment is a preventive method and it is required in high pressure boilers.
a) True
b) False
Answer: a
Clarification: External treatment is a preventive method and it is required in high pressure boilers. External treatment is carried out outside the boilers.

9. Potable water treatment does not involve __________
a) Disinfection
b) Demineralisation
c) Coagulation
d) Sedimentation
Answer: b
Clarification: Potable water treatment does not involve demineralisation. It involves disinfection, coagulation and sedimentation processes.

10. The exhausted anion exchangers can be regenerated by working with __________
a) Acid solution
b) Alcohol solution
c) Alkali solution
d) Water
Answer: c
Clarification: The exhausted anion exchangers can be regenerated by working with alkali solution because alkali solution or basic solution does not contain reactive ions.

Engineering Chemistry Multiple Choice Questions on “Steam Distillation”.

1. In steam distillation, the liquid boils when the sum of vapour pressure due to organic liquid and due to water becomes ____________
a) Greater than atmospheric pressure
b) Lesser than atmospheric pressure
c) Equals to atmospheric pressure
d) None of the mentioned
Answer: c
Clarification: In steam distillation, the liquid boils when the sum of vapour pressure due to organic liquid and due to water becomes equal to the atmospheric pressure. It is a type of distillation of a liquid in a current of steam, used especially to purify liquids that are not very volatile and are immiscible with water.

2. The organic liquid in steam distillation vaporizes at ____________
a) Lower temperature than its boiling point
b) Higher temperature than its boiling point
c) At its boiling point
d) None of the mentioned
Answer: a
Clarification: The organic liquid in steam distillation vaporizes at lower temperature than its boiling point.

3. Steam distillation process is used to separate substances which are ____________
a) Steam volatile
b) Steam volatile and immiscible with water
c) Steam volatile and miscible with water
d) All of the mentioned
Answer: b
Clarification: Steam distillation process is used to separate substances which are steam volatile and immiscible with water. It is a type of distillation of a liquid in a current of steam, used especially to purify liquids that are not very volatile and are immiscible with water.

4. What type of mixture is collected in round bottom flask after passing through a steam generator?
a) Mixture of volatile organic compound and water
b) Mixture of nonvolatile organic compound and water
c) Mixture of nonvolatile inorganic compound and steam
d) Mixture of volatile organic compound and steam
Answer: d
Clarification: Mixture of volatile organic compound and steam is collected in round bottom flask after passing through steam generator.

5. Which of the following property is not possessed by the organic solvent required to separate organic compound with water?
a) It is immiscible with water
b) It is less volatile than water
c) It is easily vaporisable
d) Organic compound is more soluble in it
Answer: b
Clarification: Organic solvent required to separate organic compound with water is more volatile liquid than water. All the other mentioned properties are possessed by the organic solvent required to separate organic compound with water.

6. Which of the following is the upper layer in differential extraction?
a) Solvent layer
b) Solute layer
c) Aqueous layer
d) None of the mentioned
Answer: a
Clarification: Solvent layer is the upper layer in differential extraction. Differential extraction refers to the process by which the DNA from two different types of cells can be extracted without mixing their contents.

7. When does the organic compound be present in the upper solvent layer in differential extraction?
a) Before the extraction
b) During the extraction
c) After the extraction
d) It is always present in the upper layer
Answer: c
Clarification: The organic compound is present in the solvent layer after the extraction. Differential extraction refers to the process by which the DNA from two different types of cells can be extracted without mixing their contents

8. The organic compound in differential extraction is recovered from the organic solvent by ____________
a) Distillation
b) Fractional crystallisation
c) Steam crystallisation
d) Sublimation
Answer: a
Clarification: The organic compound in differential extraction is recovered from the organic solvent by distillation by evaporation.

9. The pure solvent after the differential extraction cannot be used again for the extraction.
a) True
b) False
Answer: b
Clarification: The pure solvent after the differential extraction can be used again for the extraction because it remains unaltered.

10. Aniline is separated from aniline-water mixture using ____________
a) Fractional distillation
b) Fractional crystallisation
c) Steam distillation
d) All of the mentioned
Answer: c
Clarification: Aniline is separated from aniline-water mixture using steam distillation. Steam distillation is a special type of distillation (a separation process) for temperature sensitive materials like natural aromatic compounds.

Engineering Chemistry Multiple Choice Questions on “Inductive Effect”.

1. Electronegativity is defined as the power of an atom in a molecule to _____________
a) Repel electrons towards itself
b) Attract electrons towards itself
c) Expand itself
d) All of the mentioned
Answer: b
Clarification: Electronegativity is defined as the power of an atom in a molecule to attract electrons towards itself. Fluorine is the most electronegative element.

2. The factors on which electronegativity depends upon ____________
a) Valence state of atom
b) Hybridisation
c) Both valence state and hybridisation
d) None of the mentioned
Answer: c
Clarification: The factors on which electronegativity depends upon is valence state of atom and hybridisation.

3. How does the electronegativiy get affected with the negative oxidation state?
a) It decreases
b) It increases
c) It remains constant
d) None of the mentioned
Answer: a
Clarification: Electronegativity decreases with the negative oxidation state since the tendency to attract an electron will decrease with the negative charge of the anion.

4. The electronegativity of sp² hybridised atom will be ____________
a) 3.29
b) 2.48
c) 3.69
d) 2.75
Answer: d
Clarification: The electronegativity of sp² hybridised atom will be 2.75. Fluorine is the most electronegative element.

5. Which of the following is a permanent electron displacement effect?
a) Inductomeric
b) Electromeric
c) Inductive
d) All of the mentioned
Answer: c
Clarification: Inductive effect is the permanent electron displacement effect and inductomeric and electromeric are temporary electron displacement effects.

6. Arrange the following groups in the order of decreasing (+I) effect.
a) C₆H₅O^– > COO^– > CR₃ > CHR₂ > H
b) C₆H₅O^– > H > CR₃ > CHR₂ > COO^–
c) CR₃ > C₆H₅O^– > H > COO^– > CHR₂
d) C₆H₅O^– > COO^– > CHR₂ > CR₃ > H
Answer: a
Clarification: The correct order is- C₆H₅O^– > COO^– > CR₃ > CHR₂ > H.

7. Arrange the following groups in the order of decreasing (-I) effect.
a) CN > F > Br > Cl > COOH > I > H
b) COOH > CN > F > Br > Cl > I > H
c) H > COOH > CN > I > Cl > F > Cl
d) CN > COOH > F > Cl > Br > I > H
Answer: d
Clarification: The correct order is- CN > COOH > F > Cl > Br > I > H.

8. Which of the following is an application of inductive effect?
a) Bond length
b) Dipole moment
c) Strength of carboxylic acids
d) All of the mentioned
Answer: d
Clarification: Bond length, dipole moment and strength of carboxylic acids are some of the applications of inductive effect.

9. Relative basic strength of amines does not depend upon ____________
a) Inductive effect
b) Mesomeric effect
c) Steric effect
d) Stabilisation of cation by hydration
Answer: b
Clarification: Relative basic strength of amines does not depend upon mesomeric effect. This effect is used in a qualitative way and describes the electron withdrawing or releasing properties of substituents based on relevant resonance structures.

10. Due to presence of C – X polar bond in alkyl halide, alkyl halides are ____________
a) More reactive than corresponding alkane
b) Less reactive than corresponding alkane
c) Equally reactive as corresponding alkane
d) None of the mentioned
Answer: a
Clarification: Due to the presence of C – X polar bond in alkyl halide, alkyl halides are more reactive than corresponding alkane.

Engineering Chemistry Multiple Choice Questions on “Gibb’s Phase Rule”.

1. What does Gibb’s phase rule state?
a) P+F=C-1
b) P+F=C+1
c) P+F=C-2
d) P+F=C+2
Answer: d
Clarification: The above phase rule is a formula that gives the condition for finding the number of phases in a system. This phase rule can be applied to both condensed as well as normal systems.

2. What is the point at which all the three phases of a system exist?
a) Triple point
b) Sublimation point
c) Vapor point
d) Eutectic point
Answer: a
Clarification: Since at the triple point, the degree of freedom is zero (that is invariant reaction takes place at that point), therefore according to phase rule, F=C-P+2. Substituting the known values, we get P=3 (all states).

3. For water system, the number of phases at the triple point is _____________
a) 0
b) 1
c) 2
d) 3
Answer: d
Clarification: Since at the triple point, the degree of freedom is zero, while applying the formula F=C-P+2, we get the number of phases as three because C=1, F=0 (since water system forms only single component).

4. Liquid phase exists for all compositions above _________ region.
a) Eutectic region
b) Equilibrium region
c) Isometric region
d) Sublimation region
Answer: c
Clarification: In a phase region above the eutectic point, both the solid and liquid phases exist together where the region is bi variant and this region is called isometric region. Here the region has 2 degrees of freedom.

5. Select the wrong statements from the following statements with respect to a phase diagram.
a) Gives information about concentration
b) Gives information about solubility
c) Gives information on melting and boiling points
d) Gives information on relative concentration
Answer: d
Clarification: A phase diagram gives information only on the concentration of species, their solubility rate, degree of freedom and other physical properties. It does not explain about transformation rates and relative concentration (relative concentration=total concentration/equilibrium concentration).

6. Select a non-homogeneous system from the following.
a) Salt solution
b) Sugar solution
c) Glucose in water
d) Saturated solution of NaCl
Answer: d
Clarification: A homogeneous mixture is one which is miscible completely with one another. In any saturated solution, when the amount of solute reaches more than a critical point, then the solution becomes heterogeneous.

7. Select the odd statement with respect to a phase reaction.
a) Saturated solution
b) Equilibrium solution
c) Concentric solution
d) Amorphous solution
Answer: a
Clarification: A terminal solution, an intermediate solution, an equilibrium solution and concentric solutions, are the ones which take part in a phase reaction. On the other hand, a saturated solution is involved in the Lever system.

8. Which of the following is the formula for condense phase rule?
a) F=C-P+2
b) F=C-P+1
c) F=C+P-2
d) F=C+P-1
Answer: b
Clarification: In a condensed phase rule system, the phases are represented in three dimension which is not suitable for graphic purposes and hence the pressure is considered to be zero (this is helpful in drawing 2D images). Hence the formula reduces to F=C-P+2.

9. Calculate the eutectic concentration given the following data.
Pressure= 1atm
Temperature: 1^oC
a) 0
b) 2
c) 1
d) 3
Answer: c
Clarification: According to Weiss law (which suits only for phase components), concentration at equilibrium is C=T/P. therefore in this case, C=1/1=1. This law is also called as Gibbs relativity law.

10. Under what condition, will we get a stable phase diagram?
a) Solid + Liquid
b) Solid + Vapor
c) Liquid + vapor
d) Liquid + Solid
Answer: a
Clarification: According to equilibrium mixture ration, an appropriate ratio of 1:10 parts of solid and liquid along with an aqueous solution will give a stable phase product.