Category: Engineering Chemistry Objective Questions

Engineering Chemistry Multiple Choice Questions on “Colloids – 1”.

1. What is the size of colloidal particles?
a) 10-20 nm
b) More than 20 nm
c) Less than 10 nm
d) 30 to 50 nm
Answer: a
Clarification: Since colloidal are intermediate between powdered particles and suspension particles, they have a size in between these particles of about 10 to 20 nm. These are considered to be intermediate size of molecules.

2. Which of the following is a characteristic of a colloid?
a) It forms 2 layers with a solution
b) It forms turbid layers
c) It forms heterogeneous layer
d) It forms a homogeneous layer
Answer: b
Clarification: Since a colloidal particle does not from a single layer with solvents, the only possibility is to form a turbid layer where the solution is an intermediate between a miscible and immiscible solution.

3. Where does colloidal solution find application in?
a) In milk industries
b) In chromatic chemical industries
c) In crystallography
d) In textiles
Answer: a
Clarification: Since colloidal solutions can easily be emulsified with the help of emulsifying agents such as ethylene dichloride, it can find its major application in the field of dairy industries.

4. Calculate the size of the colloidal particle present in the mixture of fats and milk from the given data.
Amount of milk in litres: 20
Amount of fats in grams: 10
Time taken to mix the ingredients: 20 sec
a) 3
b) 6
c) 4
d) 61
Answer: c
Clarification: The size of the colloidal particles can be given by the formula
Size=amount of solvent x time/ amount of colloidal. Therefore in this problem, we can see that the size of the colloid is 20 x 20 / 10 = 4.

5. During an experiment, accidently iodine got mixed up with a biological sample of proteins and polys. Identify the smallest colloid that can be obtained during the process of separation.
a) Fats
b) Amino acids
c) Polys
d) R molecules
Answer: b
Clarification: Given that the solution of iodine got mixed up with milk sample, we know milk is already a colloidal solution of polymers like amino acids, proteins, fats, vitamins etc, the smallest among all these colloidal particles is amino acids.

6. Which of the following form of colloid is considered to be the strongest colloid?
a) Gel
b) Foam
c) Solid sol
d) Liquid sol
Answer: c
Clarification: We know that solid sol is the colloidal solution of a solid and a solid. Since there is a mixture of solid and solid, the bond between them is quite strong. Thus it is considered to be the strongest colloid.

7. Which of the following form of colloid is considered to be the lightest colloid?
a) Gaseous foam
b) Solid sol
c) Sol
d) Liquid sol
Answer: a
Clarification: We know that the gaseous foam is the colloidal solution of gaseous molecules and liquid. Thus there exists a lighter bond between the particles. Thus this is considered as the lightest colloid.

8. What is the size of normal an amino acid?
a) 1 to 2 nm
b) 2 to 3 nm
c) 4 to 5 nm
d) 2 to 5 nm
Answer: a
Clarification: We know that amino acids are nothing but single structure monomers of proteins. Thus they are visible only under an ultra microscope due to is an extreme small size in the range of nano meters. Their size ranges from 1 to 2 nm.

9. What is called a dispersion phase?
a) It is the main layer
b) It is the secondary layer in which the colloidal particles are dispersed
c) It is the secondary layer
d) It is the basic colloidal layer
Answer: b
Clarification: Since the colloidal particles require a layer in which it has to be dispersed, the dispersion phase is considered to be a second layer. The dispersion phase is generally a solvent.

10. What is called a dispersion medium?
a) It is where the dispersed phase settles
b) It is where the solute particles settle
c) It is where the dispersed phase is suspended
d) It is the primary medium
Answer: c
Clarification: Since to form a stable colloidal solution, the dispersed phase requires a stable solvent medium is required. This is the condition in which equilibrium is achieved. This medium is called a dispersion medium.

Engineering Chemistry Multiple Choice Questions on “E and Z Nomenclature of Geometric Isomers”.

1. What are Stereoisomers?
a) Isomers having a same molecular formula and same configuration
b) Isomers having a same molecular formula but different configuration
c) Isomers having a different molecular formula but the same configuration
d) Isomers having a different molecular formula and different configuration
Answer: b
Clarification: Stereoisomerism is exhibited by isomers having the same molecular formula but different configuration.

2. What are diastereomers?
a) Molecules with non-superimposable mirror images
b) Molecules with superimposable mirror images
c) Molecules which do not have non-superimposable mirror images
d) None of the mentioned
Answer: c
Clarification: Diastereomers are those stereomers which do not have non-superimposable mirror images.

3. Which type of compounds cannot exhibit geometrical isomerism?
a) Singly Bonded
b) Doubly Bonded
c) Triply Bonded
d) Cyclic Compounds
Answer: c
Clarification: Triply bonded compounds cannot exhibit geometrical isomerism as the -C=C- bond in these molecules is linear.

4. Choose the correct option from the following.
a) A group gets priority if its atomic number is high
b) When atoms attached to a double bond have same atomic number, the first atoms are considered
c) A group gets priority if its atomic number is low
d) Lone pair gets more priority and is ranked above hydrogen
Answer: a
Clarification: A group gets priority if its atomic number is high and When atoms attached to a double bond have same atomic number, the second atoms are considered.

5. In which type of projection we can get staggered and eclipsed conformations?
a) Newman Projection
b) Sawhorse Projection
c) Fischer Projection
d) Wedge Projection
Answer: b
Clarification: A sawhorse projection can reveal staggered and eclipsed conformations.

6. Assign E or Z configuration to the given compound.

a) E-configuration
b) Z-configuration
c) S-configuration
d) R-configuration
Answer: a
Clarification: Trans-2-butene has two geometric isomers and this is E-configuration.

7. Which of the following compounds have Z-configuration?
a) _CH3^CH₃CH₂>C=CH_CH3
b) _H^Ph>C=CCOOH_Ph
c) _H2N^Cl>C=CCOOH_Br
d) _CH3^Ph>C=CCH₂CH_3Br
Answer: b
Clarification: All the other options are in E-configuration. Only the second option shows the Z-configuration.

8. Select the incorrect option from the following.
a) Fischer projections are two dimensional representations of three dimensional molecules
b) A molecule is achiral if it cannot be superimposed on its mirror reflection
c) E and Z notations are based on Cahn, Ingold and Prelog priority system
d) Chiral molecules which are non-superimposable mirror images of each other are enantiomers
Answer: b
Clarification: A molecule is achiral if it is superimposable on its mirror reflection. All the other options are correct.

9. The cis-trans nomenclature is not applicable when _________
a) The different groups attached to the carbon atom of double bond are same
b) Atleast one of the group attached to each carbon atom is same
c) The different groups attached to the carbon atom of double bond are not same
d) The cis-trans nomenclature is applicable for all compounds
Answer: c
Clarification: The cis-trans nomenclature is applicable when the different groups attached to the carbon atom of double bond are same or atleast one of the group attached to each carbon atom is same.

10. In glyceraldehydes, the complete sequence of priority is _________
a) –OH > -CH₂OH > -CHO > -H
b) –H > -CH₂OH > -CHO > -OH
c) –H > –OH > -CH₂OH > -CHO
d) –OH > CHO > -CH₂OH > -H
Answer: d
Clarification: In glyceraldehydes, the complete sequence of priority is –OH > CHO > -CH₂OH > -H.

Engineering Chemistry Question Bank focuses on “Fractional Distillation”

1. Fractional distillation is a process of separation of ____________
a) 2 miscible liquids
b) 2 immiscible liquids
c) 1 miscible and 1 immiscible liquid
d) None of the mentioned
Answer: a
Clarification: Fractional distillation is a process of separation of 2 immiscible liquids. Fractional distillation is the separation of a mixture into its component parts, or fractions, separating chemical compounds by their boiling point by heating them to a temperature at which one or more fractions of the compound will vaporize.

2. The difference in boiling point of 2 liquid in fractional distillation is ____________
a) Greater than 25 K
b) Less than 25 K
c) Equal to 25 K
d) None of the mentioned
Answer: b
Clarification: Difference in the boiling point of 2 liquid in fractional distillation is is less than 25 K. Fractional distillation is the separation of a mixture into its component parts, or fractions, separating chemical compounds by their boiling point by heating them to a temperature at which one or more fractions of the compound will vaporize.

3. A simple fractional tube is packed with ____________
a) Wooden beads
b) Plastic beads
c) Metal beads
d) Glass beads
Answer: d
Clarification: A simple fractional tube is packed with glass beads. The fractional distillation column is set up with the heat source at the bottom on the still pot.

4. Fractional distillation is different from distillation because of the presence of ____________
a) Fractionating column
b) Condenser
c) Distillation flask
d) Conical flask
Answer: a
Clarification: Fractional distillation is different from distillation because of the presence of fractionating column. A laboratory fractionating column is a piece of glassware used to separate vaporized mixtures of liquid compounds with close volatility.

5. The beads are provided in fractional column for ____________
a) Vapours to generate
b) Vapours to condense
c) Vapours to evaporate
d) All of the mentioned
Answer: b
Clarification: The beads are provided in fractional column for vapours to condense. The fractional distillation column is set up with the heat source at the bottom of the still pot.

6. Select the incorrect statement from the following options.
a) Fractionating columns are available in various design and size
b) Fractionating columns are available according to one fixed standard
c) A simple fractionating column is a tube packed with glass beads
d) Fractional distillation is the process of separation of different gases from air
Answer: b
Clarification: Fractionating columns are available in various design and sizes and not according to one fixed standard.

7. Which of the following gases cannot be separated from air using fractional distillation?
a) Argon
b) Oxygen
c) Helium
d) Nitrogen
Answer: c
Clarification: Helium gas cannot be separated from air using fractional distillation. Fractional distillation is used in air separation, producing liquid oxygen, liquid nitrogen, and highly concentrated argon.

8. Initially, the temperature at the top of the column is _______________ than at its bottom.
a) Greater
b) Lesser
c) Equal
d) None of the mentioned
Answer: b
Clarification: The temperature at the top of the column is lesser than at its bottom. The two major types of distillation columns used are tray and packing columns.

9. Which of the following is more suitable for fractional distillation process?
a) Oil bath
b) Water bath
c) Glycerine bath
d) None of the mentioned
Answer: a
Clarification: Oil bath is the most suitable option for the fractional distillation process. Vacuum distillation systems operate at reduced pressure, thereby lowering the boiling points of the materials. Anti-bumping granules, however, become ineffective at reduced pressures.

10. Number of steps required for the separation of two liquids in fractional distillation is _________
a) 1
b) 2
c) 3
d) 4
Answer: b
Clarification: Number of steps required for the separation of two liquids in fractional distillation is 2. Vacuum distillation systems operate at reduced pressure, thereby lowering the boiling points of the materials. Anti-bumping granules, however, become ineffective at reduced pressures.

To practice Engineering Chemistry Question Bank,

Engineering Chemistry Multiple Choice Questions on “Nuclear Magnetic Resonance”.

1. The nuclei with a spin quantum number greater than _______ can exhibit the NMR phenomenon.
a) 0
b) 5
c) 10
d) -5
Answer: a
Clarification: The nuclei with a spin quantum number greater than zero can exhibit the NMR phenomenon. Nuclear magnetic resonance spectroscopy, NMR spectroscopy, is a research technique that exploits the magnetic properties of certain atomic nuclei.

2. The number of different orientations which a magnetic nucleus can take is ____________
a) 2I
b) 2I-1
c) 2I+1
d) 4I
Answer: c
Clarification: The number of different orientations that a magnetic nucleus can take is 2I+1.

3. Number of NMR signals obtained in CH₃COCH₃ will be ____________
a) 6
b) 3
c) 2
d) 1
Answer: d
Clarification: Number of NMR signals obtained in CH₃COCH₃ will be 1. Nuclear magnetic resonance spectroscopy, is a research technique that exploits the magnetic properties of certain atomic nuclei.

4. Propene as well as 2-Butene(cis) will show equal number of signals in their NMR spectra.
a) True
b) False
Answer: b
Clarification: Propene as well as 2-Butene(cis) will not show equal number of signals in their NMR spectra.

5. Select the incorrect statement from the following option.
a) TMS stands for tetra methyl silane
b) All the hydrogen in TMS have the same chemical shift
c) TMS has a high boiling point, so it is not easily lost when holding the NMR sample
d) TMS is relatively unreactive with most functional groups
Answer: c
Clarification: TMS has a low boiling point so it can be easily removed from a recoverable sample of an organic compound. All the other options are correct. TMS is relatively unreactive with most functional groups.

6. The NMR spectra of the functional isomers of the molecular formula C₂H₆O show _________ and _________ signals respectively.
a) 1, 2
b) 1, 3
c) 1, 4
d) 1, 5
Answer: b
Clarification: The NMR spectra of the functional isomers of the molecular formula C₂H₆O show one and three signals respectively.

7. The number of signals in 1-propanol are _________ while those in 2-propanol are ______
a) 4, 3
b) 4, 2
c) 2, 4
d) 3, 4
Answer: a
Clarification: The number of signals in 1-propanol are 4 while those in 2-propanol are 3.

8. For NMR spectrum, carbon tetrachloride and water can be successfully used as a solvent.
a) True
b) False
Answer: a
Clarification: For the NMR spectrum, carbon tetra-chloride and water can be successfully used as a solvent. NMR is routinely used in advanced medical imaging techniques, such as in magnetic resonance imaging (MRI).

9. In how many ways –CH₃ protons can couple with the protons on adjacent carbon atom relative to the external field.
a) 1
b) 2
c) 3
d) 4
Answer: d
Clarification: In four ways –CH₃ protons can couple with the protons on adjacent carbon atom relative to the external field.

10. Which of the following is inversely proportional to the chemical shifts positions (δ)?
a) Frequency of unknown group of protons
b) Frequency of TMS
c) Operating frequency of the instrument
d) All of the mentioned
Answer: c
Clarification: Operating frequency of the instrument is inversely proportional to the chemical shifts positions (δ).

Engineering Chemistry Multiple Choice Questions on “Catalysis”.

1. Which of the following is not a category of catalysis?
a) Homogeneous
b) Heterogeneous
c) Artificial
d) Enzymatic
Answer: c
Clarification: The four categories of catalysis are: homogeneous, heterogeneous, auto and enzymatic. Artificial is not a category of catalysis.

2. Which of the following is an example of homogeneous catalysis?
a) Enzyme catalysis
b) Hardening of animal and vegetable oils
c) Haber’s process
d) Cracking of heavy oils for a synthesis of gasoline
Answer: a
Clarification: Enzyme catalysis is an example of homogeneous catalysis. All the other options are not examples of homogeneous catalysis.

3. Which of the following act as catalysis for Williamson’s etherification process?
a) HCl
b) NaCl
c) KMnO₄
d) H₂SO₄
Answer: d
Clarification: H₂SO₄ act as catalysis for Williamson’s etherification process. The Williamson ether synthesis is an organic reaction, forming an ether from an organohalide and a deprotonated alcohol.

4. Select the incorrect statement from the following option.
a) Intermediate compound formation theory fails to explain the action of promoters
b) Intermediate compound formation theory fails to explain the function of a catalyst in homogeneous reactions
c) Intermediate compound formation theory fails to explain the action of catalytic poisons
d) Intermediate compound formation theory fails to explain the function of catalyst in heterogeneous reactions
Answer: b
Clarification: Intermediate compound formation theory explains the function of a catalyst in homogeneous reactions. All the other options are correct. But it fails to explain the action of promoters, action of catalytic poisons and function of catalyst in heterogeneous reactions.

5. Select the incorrect statement about the adsorption theory from the following option.
a) The surface of the solid catalyst possess some isolated active centres having residual affinity
b) Due to these centres, the molecules of the gaseous reactants get adsorbed in unimolecular thick layer
c) The adsorbed reactants get activated and then react
d) The energy required for activation is more than that required for uncatalysed reaction
Answer: d
Clarification: The energy required for activation is less than that required for uncatalysed reaction, and hence the reaction goes faster. All the other options are correct.

6. No definite intermediate compound formation takes place in contact theory.
a) True
b) False
Answer: a
Clarification: No definite intermediate compound formation takes place in contact theory. The contact hypothesis has been described as one of the best ways to improve relations among groups that are experiencing conflict.

7. Which of the following step is the rate determining step of contact theory?
a) Diffusion of reactants to surface
b) Adsorption of reactants at the surface
c) Chemical reaction at the surface
d) Desorption of products from the surface
Answer: c
Clarification: Chemical reaction at the surface is the slowest and rate determining step of contact theory. The contact hypothesis has been described as one of the best ways to improve relations among groups that are experiencing conflict.

8. Which of the following statement is incorrect about the adsorption theory?
a) The catalyst is more efficient in finely divided state
b) Action of promoters is not explained
c) Enhanced activity of a rough surfaced catalyst is explained
d) Specific action of catalyst is explained
Answer: b
Clarification: Action of promoters and catalytic poisons is also explained. All the other options are correct. The catalyst is more efficient in the finely divided state.

9. The factor which determines the activity of a heterogeneous catalyst is ___________
a) Total surface area only
b) The number of active sites per unit amount of catalyst only
c) Method of preparation, prior treatment only
d) Total surface area, number of active sites and method of preparation
Answer: d
Clarification: The factors which determine the activity of a heterogeneous catalyst are – Total surface area, the number of active sites per unit amount of catalyst and method of preparation, prior treatment.

10. What is the optimum temperature for Haber’s process?
a) 450⁰C
b) 45⁰C
c) 150⁰C
d) 300⁰C
Answer: a
Clarification: The optimum temperature for Haber’s process is 450⁰C. Haber’s process is an industrial process for producing ammonia from nitrogen and hydrogen, using an iron catalyst at high temperature and pressure.

11. Which of the following process is used for the manufacturing of acetic acid?
a) Bosch’s process
b) Deacon’s process
c) Vinegar process
d) Chamber process
Answer: c
Clarification: Vinegar process is used for the manufacturing of acetic acid. The term “vinegar” actually refers to the two-step process of fermentation from carbohydrate to alcohol to acetic acid.

12. Which of the following process is used for the preparation of sulphuric acid?
a) Ostwald’s process
b) Bergius process
c) Deacon’s process
d) Chamber process
Answer: d
Clarification: Chamber process is used for the preparation of sulphuric acid. Chamber process, also called Lead-chamber Process, method of producing sulfuric acid by oxidizing sulfur dioxide with moist air, using gaseous nitrogen.

Engineering Chemistry Multiple Choice Questions on “Stereo Structure of Polymers”.

1. Which of the following scientists won the noble prize for their work in polymer stereochemistry?
a) Kurt Alder and Richard Abegg
b) Peter Agre and Agricola
c) Zeigler and Natta
d) Friedrich Accum
Answer: c
Clarification: Ziegler and Natta shared the noble prize in 1963 for their work in stereochemistry of polymers.

2. A tactic dyad has a segment of the polymer chain consisting of _________ monomeric units.
a) 5
b) 2
c) 3
d) 4
Answer: b
Clarification: A tactic dyad has a segment of the polymer chain consisting of two monomeric units. Dyad means two, triad means three.

3. The polymer in which alternate chiral centres have the same configuration is called ____________
a) Syndiotactic
b) Atactic
c) Isotactic
d) Multitactic
Answer: a
Clarification: The polymer in which alternate chiral centres have the same configuration is called syndiotactic, in which the repeating units have alternating stereo chemical configurations.

4. The tendency for a polymer to adopt crystalline morphology increases with __________ stereo regularity.
a) Decreasing
b) Increasing
c) First increasing then decreasing
d) First decreasing then increasing
Answer: b
Clarification: The tendency for a polymer to adopt crystalline morphology increases with increasing stereo regularity, regardless of the type of stereochemistry.

5. The configuration of the isotactic dyad is ____________
a) Rectus
b) Racemic
c) Chiral
d) Meso
Answer: d
Clarification: The configuration of the isotactic dyad is meso. Isotactic denotes a polymer in which all the repeating units have the same stereo chemical configuration.

6. When each chiral centre has the same configuration, the polymer is called ____________
a) Atactic
b) Syndiotactic
c) Isotactic
d) Multitactic
Answer: c
Clarification: When each chiral centre has the same configuration, the polymer is called isotactic. It denotes a polymer in which all the repeating units have the same stereochemical configuration.

7. Atactic polymer is that in which?
a) Alternate chiral centres have the same configuration
b) Every third chiral centre has the same configuration
c) Each chiral centre has the same configuration
d) A complete random distribution of configuration is there
Answer: d
Clarification: Atactic polymer is that in which a complete random distribution of configuration is there. Atactic polypropylene has little order in the polymer backbone and is amorphous.

8. A tactic triad has three possible sequences, viz. (i) mm (ii) rr (iii) mr(or rm).
a) True
b) False
Answer: a
Clarification: A tactic triad has three possible sequences, viz. (i) mm (ii) rr (iii) mr(or rm). An isotactic triad (mm) is made up of two adjacent meso diads, a syndiotactic triad (rr) consists of two adjacent racemo diads and a heterotactic triad (rm) is composed of a meso diad adjacent to a racemo diad.