Generic selectors
Exact matches only
Search in title
Search in content
Search in posts
Search in pages
Filter by Categories
nmims post
Objective Type Set
Online MCQ Assignment
Question Solution
Solved Question
Uncategorized

Multiple choice question for engineering

Set 1

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

View Answer

Answer: c [Reason:] 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

View Answer

Answer: a [Reason:] 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

View Answer

Answer: b [Reason:] Steam distillation process is used to separate substances which are steam volatile and immiscible with water. It is 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 steam generator?
a) Mixture of volatile organic compound and water
b) Mixture of non volatile organic compound and water
c) Mixture of non volatile inorganic compound and steam
d) Mixture of volatile organic compound and steam

View Answer

Answer: d [Reason:] 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

View Answer

Answer: b [Reason:] 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

View Answer

Answer: a [Reason:] 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 is 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

View Answer

Answer: c [Reason:] 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 organic solvent by
a) Distillation
b) Fractional crystallisation
c) Steam crystallisation
d) Sublimation

View Answer

Answer: a [Reason:] The organic compound in differential extraction is recovered from 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

View Answer

Answer: b [Reason:] 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

View Answer

Answer: c [Reason:] 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.

Set 2

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

View Answer

Answer: c [Reason:] 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

View Answer

Answer: b [Reason:] 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 same configuration is called
a) Syndiotactic
b) Atactic
c) Isotactic
d) Multitactic

View Answer

Answer: a [Reason:] The polymer in which alternate chiral centres have 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

View Answer

Answer: b [Reason:] The tendency for a polymer to adopt crystalline morphology increases with increasing stereo regularity, regardless of the type of stereochemistry.

5. The configuration of isotactic dyad is
a) Rectus
b) Racemic
c) Chiral
d) Meso

View Answer

Answer: d [Reason:] The configuration of 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

View Answer

Answer: c [Reason:] 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

View Answer

Answer: d [Reason:] 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. State true or false. A tactic triad has three possible sequences, viz. (i) mm (ii) rr (iii) mr( or rm).
a) True
b) False

View Answer

Answer: a [Reason:] 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.

Set 3

1. The reaction which gives exclusively one of several possible isomeric products is called
a) Dynamicselective
b) Stereoselective
c) Regioselective
d) Stereospecific

View Answer

Answer: c [Reason:] The reaction which gives exclusively one of several possible isomeric products is called regioselective reaction. Regioselectivity is the preference of one direction of chemical bond making or breaking over all other possible directions.

2. The reaction that yields predominantly one enantiomer of a possible pair is called
a) Dynamicselective
b) Stereoselective
c) Regioselective
d) Stereospecific

View Answer

Answer: b [Reason:] The reaction that yields predominantly one enantiomer of a possible pair is called stereoselective reaction. Stereoselectivity is the property of a chemical reaction in which a single reactant forms an unequal mixture of stereo isomers during the non-stereo specific creation of a new stereo center or during the non-stereo specific transformation of a pre-existing one.

3. State true or false. Stereoselectivity can be exhibited in various degrees.
a) True
b) False

View Answer

Answer: a [Reason:] Stereoselectivity can be exhibited in various degrees like completely stereoselective, highly stereoselective, moderately stereoselective and so on.

4. The reaction in which stereochemically different molecules react differently is called
a) Dynamicselective
b) Stereoselective
c) Regioselective
d) Stereospecific

View Answer

Answer: d [Reason:] The reaction in which stereochemically different molecules react differently is called stereospecific reaction. Stereospecificity is the property of a reaction mechanism that lead to different stereo isomeric reaction products from different stereo isomeric reactants, or which operates on only one of the stereo isomers.

5. Which of the following is an example of regioselective reaction?
a) Debromination of 2,3- dibromobutane
b) 2-bromo octane with sodium hydroxide
c) Addition of HI to propylene
d) Debromination of meso dibromobutane

View Answer

Answer: c [Reason:] Addition of HI to propylene is an example of regioselective reaction. Regioselectivity is the preference of one direction of chemical bond making or breaking over all other possible directions.

6. Reaction of (±) 2,3- dibromobutane is slower than meso in which the two methyl groups are
a) Skew
b) Anti
c) Gauche
d) Partially eclipsed

View Answer

Answer: d [Reason:] Reaction of (±) 2,3- dibromobutane is slower than meso due to higher transition state in which the two methyl groups are partially eclipsed.

7. State true or false. Dynamic stereochemistry helps in correlating conformation and reactivity and in stereoselective synthesis.
a) True
b) False

View Answer

Answer: a [Reason:] Dynamic stereochemistry helps in correlating conformation and reactivity and in stereoselective synthesis. Stereoselectivity is the property of a chemical reaction in which a single reactant forms an unequal mixture of stereo isomers during the non-stereo specific creation of a new stereo center

8. R – C = C – R reacts in the presence of lindlar catalyst to give syn product. This is an example of
a) Dynamicselective
b) Stereoselective
c) Regioselective
d) Stereospecific

View Answer

Answer: b [Reason:] The above mentioned reaction is an example of stereoselective reaction. Stereoselectivity is the property of a chemical reaction in which a single reactant forms an unequal mixture of stereo isomers during the non-stereo specific creation of a new stereo center

9. Under SN2 conditions, on reaction with NaOH, (R)-2-bromo octane gives
a) (S)-2-octanol
b) (R)-2-octanol
c) Trans-2-butene
d) Cis-2-butene

View Answer

Answer: a [Reason:] Under SN2 conditions, on reaction with NaOH, (R)-2-bromo octane gives (S)-2- octanol. In SN2 mechanism, one bond is broken and one bond is formed synchronously.

10. Under SN2 conditions, on reaction with NaOH, (S)-2-bromo octane gives (R)-2-octanol. This is an example of
a) Dynamicselective
b) Stereoselective
c) Regioselective
d) Stereospecific

View Answer

Answer: d [Reason:] Under SN2 conditions, on reaction with NaOH, (S)-2-bromo octane gives (R)-2-octanol. This is an example of stereospecific reaction. In SN2 mechanism, one bond is broken and one bond is formed synchronously.

11. Optical purity is defined as the
a) Ratio of rotation of pure enantiomer to rotation of mixture
b) Ratio of rotation of mixture to rotation of pure enantiomer
c) Product of rotation of mixture and rotation of pure enantiomer
d) Sum of rotation of mixture and rotation of pure enantiomer

View Answer

Answer: b [Reason:] Optical purity is defined as the ratio of rotation of mixture to rotation of pure enantiomer. It is expressed as a percentage. If the sample only rotates plane-polarized light half as much as expected, the optical purity is 50%.

12. The formula of enantiomeric excess is
a) [(d+l)/(d-l)]*100
b) [(d)/(d+l)]*100
c) [(d-l)/(d)]*100
d) [(d-l)/(d+l)]*100

View Answer

Answer: c [Reason:] The formula of enantiomeric excess is [(d-l)/(d+l)]*100. It gives the percentage of excess of an enantiomer.

Set 4

1. The unit of surface tension in CGS system is
a) N/m
b) Kg/cm
c) Dynes/cm
d) Dynes/m

View Answer

Answer: c [Reason:] The unit of surface tension in CGS system is dynes/cm. It is N/m in S.I. system. Surface tension is the elastic tendency of a fluid surface which makes it acquire the least surface area possible.

2. The apparatus used for the determination of surface tension of a liquid is
a) Oedometer
b) Stalagmometer
c) Consolidometer
d) None of the mentioned

View Answer

Answer: b [Reason:] The apparatus used for the determination of surface tension of a liquid is called stalagmometer. It is equivalent to force per unit length.

3. Stalagmometer is cleaned to remove grease with the help of
a) Chromic acid
b) Sulphuric acid
c) Distilled water
d) Tartaric acid

View Answer

Answer: a [Reason:] Stalagmometer is cleaned to remove grease with the help of chromic acid. It is used for the determination of surface tension.

4. The surface tension of water at 250C is
a) 90.0 dynes/cm
b) 45.63 dynes/cm
c) 82.5 dynes/cm
d) 72.14 dynes/cm

View Answer

Answer: d [Reason:] The surface tension of water at 250C is 72.14 dynes/cm. It is a standard value.

5. On increasing the temperature, the kinetic energy of the liquid molecules
a) Increases
b) Decreases
c) Remains constant
d) None of the mentioned

View Answer

Answer: a [Reason:] On increasing the temperature, the kinetic energy of the liquid molecules also increases. At high temperature, randomness increases.

6. In case of water and glass, we get a concave meniscus because the adhesive force between water and glass are _______________ than the cohesive forces between water molecules.
a) Weaker
b) Stronger
c) Same
d) None of the mentioned

View Answer

Answer: b [Reason:] In case of water and glass, we get a concave meniscus because the adhesive force between water and glass are stronger than the cohesive forces between water molecules.

7. Shapes of drops of liquid are spherical because of
a) Viscosity
b) Conductivity
c) Absorption
d) Surface tension

View Answer

Answer: d [Reason:] Shapes of drops of liquid are spherical because of surface tension as it reduces the surface area to a minimum.

8. Select the incorrect statement from the following option.
a) In case of mercury and glass, we observe a convex meniscus
b) Surface tension is responsible for the rise and fall of the capillary tubes
c) If two drops encounter each other, they tend to repel each other
d) All of the mentioned

View Answer

Answer: c [Reason:] If two drops encounter each other, they tend to coalesce into a large drop. All the other options are correct. In case of mercury and glass, we observe a convex meniscus and Surface tension is responsible for the rise and fall of the capillary tubes.

9. On increasing the temperature, the surface tension of the liquid
a) Increases
b) Decreases
c) Remains constant
d) None of the mentioned

View Answer

Answer: b [Reason:] On increasing the temperature, the surface tension of the liquid decreases. It is inversely proportional to the temperature.

10. Which of the following is an application of surface tension?
a) Use of soaps and detergents as cleansing agents
b) Molecular structure can be elucidated by surface tension measurements through parachor values
c) Surfactants are incorporated in preparations like toothpaste
d) All of the mentioned

View Answer

Answer: d [Reason:] Use of soaps and detergents as cleansing agents, molecular structure can be elucidated by surface tension measurements through parachor values and surfactants are incorporated in preparations like toothpaste are the applications of surface tension.

Set 5

1. The thermoplastic is
a) Cross-linked
b) Insoluble
c) Amorphous
d) Held by covalent bond

View Answer

Answer: c [Reason:] Thermoplastics are linear or branched, soluble in suitable solvents, amorphous or semi-crystalline and held together by weak vander waal’s force or hydrogen bonds.

2. Which of the following is not an example of thermoplastic?
a) Nylon
b) Polyester
c) PVC
d) Vulcanised rubber

View Answer

Answer: d [Reason:] The examples of thermoplastic are nylon, polyester, PVC,PE, PP, PVA etc.

3. Polythene is prepared by the process of __________________ polymerisation of ethylene.
a) Addition
b) Condensation
c) Living
d) Free-radical

View Answer

Answer: a [Reason:] Polythene is prepared by the process of addition polymerisation of ethylene. Polythene is of low strength, hardness and rigidity, but has a high ductility and impact strength as well as low friction.

4. LDPE is prepared by polymerising ethylene at a pressure of
a) 100-200 atmospheres
b) 1000-5000 atmospheres
c) 10-100 atmospheres
d) 2-10 atmospheres

View Answer

Answer: b

5. The crystallinity of LDPE is
a) 10%
b) 30%
c) 55%
d) 80-90%

View Answer

Answer: c [Reason:] The crystallinity of LDPE is low (55%). LDPE is defined by a density range of 0.910–0.940 g/cm3.

6. Select the incorrect statement from the following option.
a) LDPE is chemically inert and has excellent chemical resistance
b) LDPE is tough and flexible
c) LDPE is used for making films in general packaging, carrier bags etc
d) LDPE has high rigidity and is suitable for load bearing applications

View Answer

Answer: d [Reason:] LDPE has low rigidity and is not suitable for load bearing applications. All other options are correct.

7. State true or false. LDPE is suitable for manufacture of pipes for distribution of gas.
a) True
b) False

View Answer

Answer: b [Reason:] LDPE is not suitable for manufacture of pipes for distribution of gas because it is permeable to gas molecules. LDPE is widely used for manufacturing various containers, dispensing bottles, wash bottles etc.

8. The ethylene is polymerised under in the presence of
a) Zeigler Natta catalyst
b) Supported metal oxide catalyst
c) Lewis acids catalyst
d) Friedel crafts catalyst

View Answer

Answer: a [Reason:] The ethylene is polymerised under 6-7 atmospheric pressure at 60-700C in the presence of Zeigler Natta catalyst.

9. The softening temperature of HDPE is
a) 200C
b) 850C
c) 1350C
d) 1500C

View Answer

Answer: c [Reason:] The softening temperature of HDPE is 1350C. HDPE is known for its large strength-to-density ratio.The density of HDPE can range from 0.93 to 0.97 g/cm3 or 970 kg/m3.

10. Select the incorrect statement from the following option.
a) HDPE has excellent electrical insulation properties
b) HDPE is free from odour and toxicity
c) HDPE can be used for domestic water and gas piping
d) HDPE possess lower tensile strength compared to LDPE

View Answer

Answer: d [Reason:] HDPE possess greater tensile strength compared to LDPE. All the other options are correct.