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Multiple choice question for engineering

Set 1

1. What colour change is observed when few drops of alcoholic NaOH is added to polyvinyl chloride solution?
a) colourless to red
b) colourless to yellow
c) colourless to blue
d) colourless to grey

View Answer

Answer: b [Reason:] When few drops of alcoholic NaOH is added to the solution of polyvinyl chloride then the mixture changes from colourless to yellow, yellow-brown, dark-brown to black with time.

2. Which polymer gives dark brown precipitate when its pyridine solution is heated in the presence of alcoholic NaOH solution?
a) polyvinylidene chloride
b) polyvinyl chloride
c) polyvinyl alcohol
d) all of the mentioned

View Answer

Answer: b [Reason:] When pyridine solution of polyvinyl chloride is heated in the presence of few drops of alcoholic NaOH solution, eventually dark brown precipitate is obtained.

3. What colour is developed when polyvinylidene chloride is immersed in morpholine?
a) dark blue
b) light yellow
c) brown
d) purple

View Answer

Answer: When polyvinylidene chloride is immersed in morpholine, it develops a brown colour both in liquid and partially swollen polymer.

4. A small volume of iodine solution when added to acidic solution of polymer X produced a blue colour immediately. An addition of pinch of borax resulted the same. Which of the following could be X?
a) polyvinyl acetate
b) polyvinyl alcohol
c) polyvinyl chloride
d) polyvinylidene chloride

View Answer

Answer: b [Reason:] Polyvinyl alcohol when treated with iodine solution develops blue colour solution.

5. What colour is obtained when polyvinyl acetate is brought in contact with iodine solution?
a) brown
b) blue
c) yellow
d) black

View Answer

Answer: a [Reason:] Polyvinyl acetate when brought in contact with dilute iodine solution gives deep brown colour.

6. A sample of polystyrene is warmed under reflux in concentrated nitric acid and the clear mixture is poured in water to yield a X coloured precipitate. This precipitate is then extracted with ether and then with NaOH solution followed by washing with water in each extraction. The nitro compounds from the combined final aqueous extract and alkaline extract using concentrated HCl and zinc. The final solution after being diazotized and then cooled is poured into excess of alkaline naphthol to give Y coloured solution. What are the colours X and Y?
a) pale yellow and deep red
b) deep blue and deep brown
c) deep red and light pink
d) light yellow and brown

View Answer

Answer: a [Reason:] When polystyrene is paased through this test, initially pale yellow colour is formed and then finally a deep red colour solution is formed.

7. Which of the following polymer does not produce yellow flame on heating?
a) phenol-formaldehyde resin
b) nylons
c) cellulose
d) nitrile rubber

View Answer

Answer: b [Reason:] Nylons produce blue flame with a yellow tip on heating.

8. A polymer X produces a pale yellow flame with light blue-green edge on heating. It produces a fish like odour and is alkaline in nature. Which of the following polymer represents X?
a) phenol formaldehyde resin
b) melamine formaldehyde resin
c) nylons
d) butyl rubber

View Answer

Answer: b [Reason:] Melamine formaldehyde resin produces a similar flame and produces a fish like smell on heating.

9. Which of the following polymer produces camphor like odour on heating?
a) ethyl cellulose
b) cellulose nitrate
c) polyacrylonitrile
d) cellulose acetate

View Answer

Answer: b [Reason:] Cellulose nitrate produces camphor like smell as it is plasticized with camphor.

10. Which of the following polymers does not produce a smoky flame?
a) polybutadiene rubber
b) gutta percha
c) poly (vinyl acetate)
d) polysulphide rubber

View Answer

Answer: d [Reason:] Polysulphide rubbers produce a bluish, smoke free flame while the rest other rubbers produce smoky flame.

11. Which of the following polymers do not produce black residue on heating?
a) chlorinated rubber
b) poly (vinyl alcohol)
c) poly (vinyl chloride)
d) none of the mentioned

View Answer

Answer: d [Reason:] All the polymers mentioned, i.e. chlorinated rubber, poly vinyl alcohol and poly vinyl chloride produce black residue on heating.

12. Which of the following polymer produces an odour resembling burning paraffin wax on heating?
a) polyethylene
b) polyesters
c) cellulose
d) butyl rubber

View Answer

Answer: a [Reason:] Polyethylene produces a smell like burning paraffin wax on heating.

13. Polymers of type A produce yellow smoky flame on heating with an unpleasant and sweet smell. They also melt or char giving acidic distillate and black residue.
Which of the following could be A?
a) polyisoprenes
b) polyesters
c) nylons
d) ethyl cellulose

View Answer

Answer: b [Reason:] Polyesters produce yellow smoky flame with unpleasant and sweet smell on heating. It chars giving acidic distillate and black residue.

14. What is the colour of flame when chlorinated rubber is heated?
a) blue
b) blue green
c) yellow
d) yellow green

View Answer

Answer: d [Reason:] Chlorinated rubber produces a yellow green flame with strongly acidic fumes on heating.

15. Which of the following polymer continues to burn even on the removal from flame?
a) chlorinated rubber
b) poly vinyl chloride
c) butyl rubber
d) nylons

View Answer

Answer: c [Reason:] Butyl rubber continues to burn even on the removal from flame while the rest other polymers burns but self extinguishes on removal from flame.

Set 2

1. Which of the following mechanism can produce a copolymer?
a) step-growth mechanism
b) free radical mechanism
c) cationic mechanism
d) all of the mentioned

View Answer

Answer: d [Reason:] Copolymers can be produced by both step-growth mechanism and chain- growth mechanism, which can occur by free radical as well as ionic mechanisms.

2. How is the reactivity of a chain radical practically determined in a free radical copolymerization?
a) number of the monomers present
b) free radical bearing terminal monomer unit
c) size of the monomer unit
d) chemical nature of monomer unit

View Answer

Answer: b [Reason:] The reactivity of a chain radical in free radical polymerization is practically determined by the free radical bearing terminal monomer unit. The size and chemical nature of the part preceding the radical bearing terminal unit is of very little significance.

3. How many propagation reactions occur simultaneously in a binary copolymerization process?
a) 2
b) 4
c) 1
d) 3

View Answer

Answer: b [Reason:] In binary copolymerization, there are two different chain radicals which can add both the monomers, though not necessarily with same ease, the system characterizes four simultaneous propagation reactions.

4. What does the copolymer composition depend upon, in binary copolymerization?
a) feed monomer composition
b) initiator concentration
c) rate of polymerization
d) all of the mentioned

View Answer

Answer: a [Reason:] It is clear from the copolymer equation that copolymer composition is dependent on the feed monomer composition. {[M1]/[M2]}copolymer = {[M1/[M2]}(r1[M1]+[M2])/(r2[M2]+[M1]) Also, there is absence of initiator and termination rate constants in the copolymer equation, which makes the composition independent of these terms.

5. Consider the copolymer equation of binary copolymerization between monomers M1 and M2
{[M1]/[M2]}copolymer = {[M1/[M2]}(r1[M1]+[M2])/(r2[M2]+[M1])
What does the term [M1] on the right hand signify here?
a) absolute molar concentration of monomer M1
b) molar concentration of monomer M1 in feed
c) molar concentration of monomer M1 in copolymer
d) none of the mentioned

View Answer

Answer: b [Reason:] The term [M1] on the right hand side is the molar concentration of monomer M1 in the feed or reaction mixture.

6. In most cases, the copolymer composition is not measurably affected due to the presence of solvents and additives. State true or false.
a) True
b) False

View Answer

Answer: a [Reason:] The composition is controlled by the kinetic factors, i.e. the reactivity ratios, r1 and r2, which are not affected by the initiator concentration, rate of polymerization and presence of solvents or additives. So the copolymer composition remains unaffected by such factors.

7. Which of the following has more priority, in binary copolymerization involving monomers M1 and M2, if the reactivity ratio r1 is greater than 1?
a) chain radical ∙M1 to add monomer M1
b) chain radical ∙M1 to add monomer M2
c) chain radical ∙M2 to add monomer M1
d) chain radical ∙M2 to add monomer M2

View Answer

Answer: a [Reason:] The reactivity ratio r1 is given by- r1= k1,1/k1,2 i.e. the ratio of homo-propagation rate constant to cross propagation rate constant, involving the chain radical ∙M1. When r1 is greater than 1, it signifies that chain radical ∙M1 has a preference to add monomer M1.

8. The values of reactivity ratios, r1 and r2 are independent of the change in the mechanism of chain propagation, form radical to ionic mechanism. State true or false.
a) True
b) False

View Answer

Answer: b [Reason:] The values of reactivity ratios significantly change for a drastic change in the mechanism of chain propagation from free radical to ionic, and even from cationic to anionic mode of chain propagation.

9. How is the monomer units arranged generally, in the copolymer structure of any vinyl copolymer?
a) sequentially
b) alternatively
c) randomly
d) all of the mentioned

View Answer

Answer:c [Reason:] In general, the monomer units in a copolymer structure are arranged in a random manner.

10. Where is the copolymer equation of binary copolymerization not applicable?
a) free radical systems
b) cationic systems
c) anionic systems
d) none of the mentioned

View Answer

Answer: d [Reason:] The copolymer equation is relevant and applicable to radical, cationic and anionic systems, despite variations in values of reactivity ratios depending on the mode of chain propagation.

Set 3

1. Which is the most widely used polymerization technique to produce polyvinyl actate?
a) bulk polymerization
b) solution polymerization
c) emulsion polymerization
d) all of the mentioned

View Answer

Answer: c [Reason:] Poly vinyl acetate is generally used as emulsion, and therefore emulsion polymerization is widely employed for the production of poly vinyl acetate. Bulk polymerization of vinyl acetate poses difficulties at high conversions due to its high exothermic nature.

2. What is the nature of commercially used poly vinyl acetate?
a) atactic
b) synditactic
c) isotactic
d) none of the mentioned

View Answer

Answer: a [Reason:] The commercially used poly vinyl acetate is atactic and hence, amorphous in nature. It has a poor dimensional stability.

3. In which of the following solvents, is polyvinyl acetate immiscible?
a) benzene
b) methanol
c) ethanol
d) acetone

View Answer

Answer: c [Reason:] PVA is soluble in benzene and acetone, and methanol. It is immiscible in ethanol.

4. Why is vinyl alcohol not polymerized to give Poly vinyl alcohol?
a) tautomerism of vinyl alchol
b) free state existence
c) infeasible reaction
d) water insoluble

View Answer

Answer: a [Reason:] The monomer, vinyl alcohol, does not exists in free state and being unstable, it forms a stable tautomer, acetaldehyde. This is why, polyvinyl acetate is used as the starting material for production of polyvinyl alcohol.

5. Polyvinyl alcohol is atactic in nature and hence amorphous. Therefore, it cannot be used as crystalline fibres. State true or false.
a) true
b) false

View Answer

Answer: b [Reason:] Although polyvinyl alcohol has atactic chain structure and hence it is amorphous in nature. However, it can be stretched into crystalline fibre due to small size OH groups which lets it fit into the crystal lattice.

6. Which of the following pair lead to the formation of polyvinyl acetals?
a) Polyvinyl alcohol + aldehydes
b) Polyvinyl alcohol + esters
c) Polyvinyl chloride + aldehydes
d) Polyvinyl acetate + ester

View Answer

Answer: a [Reason:] Polyvinyl acetals are formed by the interaction of polyvinyl alcohol and various aldehydes. The reaction usually involves condensation between I,3- hydroxyl groups and aldehyde group.

7. Which among the following is the important commercial use of polyvinyl butyral?
a) film forming technology
b) safety glass interlayer
c) textile and paper treatment
d) decorative laminates

View Answer

Answer: b [Reason:] The commercial importance of polyvinyl butyral is its use as a safety glass interlayer, particularly because of its excellent clarity, toughness and exceptional adhesion o glass.

8. Why is reaction between polyvinyl alcohol and butyraldehyde for the formation of polyvinyl butyral, which is to be used for safety glass application, is stopped at about 75% conversion?
a) high heat is generated
b) polyvinyl butyral precipitates out
c) certain amount of monomer should be left unreacted
d) none of the mentioned

View Answer

Answer: c [Reason:] For the purpose of safety glass application, the reaction is stopped at about 75% conversion, so that nearly 25% monomer is left unreacted which would provide the required strength and adhesion to the glass.

9. What happens when the degree of alcoholysis of polyvinyl alcohol is increased beyond 90%?
a) water solubility increases
b) water solubility decreases
c) decolouration occurs
d) water insolubility

View Answer

Answer: a [Reason:] The polymer of vinyl alcohol having a degree of alcoholysis beyond 90%, its water solubility then follows an increasing trend with increasing degree of alcoholysis.

10. Which of the following is used as a catalyst in the formation of polyvinyl butyral?
a) Na2SO4
b) H2SO4
c) CrO3
d) (CH3COO)2Cd

View Answer

Answer: b [Reason:] The reaction between polyvinyl alcohol and butyraldehyde requires the presence of acid catalyst like H2SO4 for the formation of polyvinyl butyral.

Set 4

1. What color of the medium is obtained when styrene is added to the naphthalene anion for initiation of polymerization?
a) blue
b) orange
c) colorless
d) green

View Answer

Answer: b [Reason:] On addition of styrene monomer to the solution containing naphthalene radical, the medium gains an orange color due to the formation of orange colored styryl radical anions by transfer of an electron to the styrene monomer from the naphthalene anion radical.

2. The polymerization of methacrylonitrile using lithium metal in liquid ammonia takes place at a much faster rate than the lithium amide (LiNH2) in liquid ammonia. State true or false.
a) true
b) false

View Answer

Answer: a [Reason:] The polymerization of methacrylonitrile using lithium metal in liquid ammonia takes place at a much faster rate than the corresponding amide (LiNH2) in liquid ammonia. This is because, metallic lithium initiates through the agency of solvated electrons formed in ammonia solution. Li + NH3 → Li+(NH3) + e(NH3).

3. What is the color of the metallic lithium in liquid ammonia solution?
a) orange
b) light green
c) deep blue
d) colorless

View Answer

Answer: c [Reason:] The deep blue color of the solution is due to the presence of solvated electrons.

4. What is the average degree of polymerization when styrene in polymerized using sodium naphthalene? (v is the average kinetic chain length)
a) 2v
b) v
c) 3v
d) v/2

View Answer

Answer: a [Reason:] The average degree of polymerization is 2v in case of polymerization of styrene using sodium naphthalene, because the radicals form di-anions and propagates the chain at both ends.

5. Which of the following anionic initiators give the slowest polymerization rate in a non-polar medium?
a) sodium naphthalene
b) butyl lithium
c) metallic lithium in NH3
d) none of the mentioned

View Answer

Answer: b [Reason:] In non-polar media, the initiator BuLi associates to degree of about 6 and the propagating species also associate. This results in the slow polymerization rate and longer time for complete conversion as compared to other anionic initiators.

6. How is the molecular weight distributed in the living polymers?
a) uniform
b) non-uniform
c) may be uniform or non-uniform
d) cannot be said

View Answer

Answer: a [Reason:] The non-termination of polymers lead to the production of mono-disperse polymers which have uniform molecular weight distribution.

7. What is the utilization of living polymerization?
a) synthesis of block polymers
b) synthesis of functional-ended polymers
c) monodisperse polymers
d) all of the mentioned

View Answer

Answer: d [Reason:] Living polymerization enables the formation of block polymers by adding a fresh monomer to the reaction. It results in the production of mono-disperse polymers and can also help in generating the functional –ended polymers by reacting the living ends with different reagents.

8. What is the application of star-shaped polystyrene produced by living polymerization with trifunctional initiator?
a) elastomers
b) rheology control
c) adhesives
d) dispersing agent

View Answer

Answer: b [Reason:] The Star –shaped polystyrene polymer is used for the rheology control and are also used as strengthening agents.

9. Which of the following end group is formed when polystyrene is made to react with ethylene oxide?
a) carboxylic group
b) hydroxyl group
c) amine group
d) no end group

View Answer

Answer: b [Reason:] Hydroxyl end groups are obtained on the reaction of polystyrene with ethylene oxide.

10. What are the functions of the bifunctional hydroxyl ended polymer formed by living polymerization technique?
a) cross-linking agents
b) elastomer synthesis
c) chain extension
d) all of the mentioned

View Answer

Answer: d [Reason:] The bifunctional hydroxyl ended group polymer helps in elastomer synthesis and chain extension and also used as cross-linking agents.

Set 5

1. Which of these words is correct?
a) Longevity
b) Longivity
c) Longevety
d) Longeviety

View Answer

Answer: a [Reason:] The correct word is Longevity. It is often misspelt. Other such words are liquefy, liaison, mystique, propeller, etc..

2. Choose the correct statement :
a) Please open the light.
b) Please shut the light.
c) Please turn on the light.
d) Please shut down the light.

View Answer

Answer: c [Reason:] The correct statement is : Please turn on the light. We turn on or off the light. We don’t open or shut the light.

3. Choose the correct statement :
a) He comes always late for practice.
b) He always comes late for practice.
c) He comes late always for practice.
d) He comes late for practice always.

View Answer

Answer: b [Reason:] The correct statement is : He always comes late for practice. Adverbs of indefinite time like, ever, never, sometimes and the adverbs almost, hardly, nearby are placed before the principal verb.

4. Fill in the blank :
I could not _____ him to come to the party.
a) convince
b) persuade
c) push
d) force

View Answer

Answer: b [Reason:] The correct statement is : I could not persuade him to come to the party. To convince is to make a person behave. To persuade means to get a person to do something.

5. Choose the correct statement:
a) Graham Bell discovered the telephone.
b) Graham Bell found the telephone.
c) Graham Bell invented the telephone.
d) Graham Bell did the telephone.

View Answer

Answer: c [Reason:] The correct statement is : Graham Bell invented the telephone. To discover means to find that which already existed. To invent means to make that which did not exist.

6. The word “ultrasonic” is a noun.
a) True
b) False

View Answer

Answer: b [Reason:] The statement is false. The word “ultrasonic” is an adjective whereas the word “ultra sound” is a noun.

7. Choose the correct statement :
a) I met him six years before.
b) I met him six years early.
c) I met him six years ago.
d) I met him six years behind.

View Answer

Answer: c [Reason:] The correct statement is : I met him six years ago. We use ago in counting from the time of speaking to a point in the past; we use before in counting from a distance to a nearer point in the past.

8. The word “cross-section” is a verb.
a) True
b) False

View Answer

Answer: a [Reason:] The statement is true. The word “cross-section” is a verb whereas the word “cross section” is a noun. Similarly, the word “cut out” is a verb and “cutout” a noun.

9. Choose the correct statement :
a) I am presently working in Mumbai.
b) I am at present working in Mumbai.
c) I am at presently working in Mumbai.
d) I am present working in Mumbai.

View Answer

Answer: b [Reason:] The correct statement is : I am at present working in Mumbai. At present means now and presently means soon.

10. Choose the correct statement :
a) This shop has many rich clients.
b) This shop has many rich customers.
c) This shop has many rich people.
d) This shop has many rich trespassers.

View Answer

Answer: b [Reason:] The correct statement is : This shop has many rich customers. A person is a client to a lawyer, a bank, etc., but not to a shop.

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