Explore topic-wise MCQs in Graduate Aptitude Test (GATE).

This section includes 43 Mcqs, each offering curated multiple-choice questions to sharpen your Graduate Aptitude Test (GATE) knowledge and support exam preparation. Choose a topic below to get started.

1.

For polymerization of vinyl acetate with hydrogen peroxide at 60ᵒC, the reciprocal of number average degree of polymerization is given by,
1/Xn = 1.75*10-4 + 14.0Rp + 5.4*104Rp2
What is the value of monomer transfer constant?

A. 1.75*10-4
B. 0.875*10-4
C. 5.4*104
D. 14
Answer» B. 0.875*10-4
2.

What is the effect of polymer transfer on the polymer product formed by radical polymerization?

A. becomes less crystallizable
B. becomes mechanically weak
C. becomes less resistant to foreign agents
D. all of the mentioned
Answer» E.
3.

What is the slope of the linear plot of log [S] v/s log [M] in significant solvent transfer mechanism?

A. CM
B. CS
C. ktr,S
D. CI
Answer» C. ktr,S
4.

Which of the following solvents is not useful for controlling the degree of polymerization?

A. carbon tetra-bromide
B. pentaphenyl ethane
C. t-butyl mercaptan
D. toluene
Answer» E.
5.

How does the value of solvent transfer constant, CS vary in the solvents with increasing substitution at the α-carbon?

A. increases
B. decreases
C. constant
D. none of the mentioned
Answer» B. decreases
6.

What is the value of intercept and slope of the straight line, when the term [1/Xn– [(y+2)/(y+1)](kt/kp2)(Rp/[M]2)] is plotted against the ratio [I]/[M], when both monomer and initiator transfer are considered?

A. CM, CI
B. CI, CM
C. 0, CI
D. none of the mentioned
Answer» B. CI, CM
7.

What is the value of intercept, when (1/Xn) is plotted against Rp, if only monomer transfer has a significant occurence?

A. 0
B. CM
C. CI
D. [I]
Answer» C. CI
8.

What is the value of chain transfer constant for a transfer agent?

A. rate constant for chain transfer reaction, ktr
B. product of ktr and kp
C. ratio of ktr to kp
D. none of the mentioned
Answer» D. none of the mentioned
9.

How is the value of average degree of polymerization defined, considering the chain transfer mechanism?

A. ratio of overall rate of polymerization to total rate of production of pairs of chain ends
B. ratio of total rate of production of chain ends to overall rate of polymerization
C. ratio of overall rate of polymerization to rate of formation of pairs of chain ends by chain transfer
D. ratio of rate of formation of pairs of chain ends by chain transfer to overall rate of polymerization
Answer» B. ratio of total rate of production of chain ends to overall rate of polymerization
10.

What does the effect of chain transfer on Rp depend on?

A. re-initiation rate constant, ki’
B. monomer concentration
C. ki’/kp
D. none of the mentioned
Answer» D. none of the mentioned
11.

Which order kinetics does the rate of polymer formation, in free radical polymerization, follow corresponding to monomer concentration?

A. 10
B. 0
C. 2
D. 3
Answer» B. 0
12.

How does polymerization rate at a given monomer concentration vary, if rate of chain initiation is tripled?

A. doubled
B. tripled
C. increment by factor of 30.5
D. remains constant
Answer» D. remains constant
13.

Consider following data for bulk polymerization, with benzoyl peroxide as initiator.
[I] = 6 mol/m3
[M] = 6.56*103 mol/m3
kp2/kt = 1.5*10-6 m3/ mol-s
What is the initiator efficiency if initial rate of polymerization is 0.0256 m3/ mol-s benzoyl peroxide decomposes at a rate of 3.2* 10-6 m3/ mol-s-1?

A. 0.7
B. 0.53
C. 0.26
D. 0.82
Answer» C. 0.26
14.

What is the expression for rate of termination reaction of free radical polymerization?

A. kt[M∙]2
B. 2kt[M∙]2
C. 2fkt[M∙]
D. fkt[M∙]
Answer» C. 2fkt[M∙]
15.

What is the rate chain initiation reaction for initiator efficiency of 0.8, when concentration and decomposition rate of benzoyl peroxide are 4 mol/m3 and 3.24*10-6 m3/ mol-s-1, respectively?

A. 2.07*10-5
B. 1.57*10-5
C. 3.27*10-5
D. 1.03*10-5
Answer» B. 1.57*10-5
16.

The data for bulk chain polymerization having potassium persulfate as initiator is given-
[I] = 5 mol/m3
[M] = 5.3*103 mol/m3
kp2/kt = 0.85*10-6 m3/ mol-s
What is the initial rate of polymerization, if potassium persulfate decomposes at a rate of 2.2*10-6 m3 s/ mol?

A. 0.012
B. 0.0162
C. 0.05
D. 0.1
Answer» C. 0.05
17.

What is the expression for the rate of chain initiation of free radical chain growth polymerization?

A. fkd[I]
B. 2fkd[I]
C. kd[I]/2
D. kd[I]
Answer» C. kd[I]/2
18.

What is the initiator efficiency in chain initiation step of free radical polymerization?

A. fraction of unreacted monomers
B. extent of reaction
C. fraction of radicals actually contributing
D. number of initiator molecules
Answer» D. number of initiator molecules
19.

How many initiator fragments are present in the dead polymer formed by combination mode of chain termination?

A. 2
B. 1
C. 3
D. 0
Answer» B. 1
20.

Which reaction may allow the biphasic interfacial polymerization technique?

A. addition polymerization
B. condensation polymerization
C. both of the mentioned
D. none of the mentioned
Answer» C. both of the mentioned
21.

Fully grown polymers are formed at the incidence of termination reaction in addition polymerization reaction. State true or false.

A. true
B. false
Answer» B. false
22.

The process in which molecular weight control is achieved by using a stoichiometric imbalance of the reacting functional group is ___________

A. chain growth process
B. step growth process
C. substitution process
D. none of the mentioned
Answer» C. substitution process
23.

Which of the following polymerization can be carried out in melt condition or in solution state?

A. addition polymerization
B. condensation polymerization
C. both of the mentioned
D. none of the mentioned
Answer» D. none of the mentioned
24.

Which of the following polymers contains −C−C− linkages only?

A. addition polymers
B. condensation polymers
C. copolymers
D. none of the mentioned
Answer» B. condensation polymers
25.

What does the reaction mixture of addition polymerization contain at any instant of time?

A. full grown polymer molecules
B. unreacted monomer molecules
C. free radical chains and initiators
D. all of the mentioned
Answer» E.
26.

The process in which the molecular weight of polymer almost remains unchanged with the progress of reaction is a ___________

A. addition polymerization
B. condensation polymerization
C. copolymerization
D. none of the mentioned
Answer» B. condensation polymerization
27.

How does the monomer conversion vary at the early stage of step-growth polymerization?

A. faster
B. slower
C. steady
D. none of the mentioned
Answer» B. slower
28.

The chain growth process is usually much slower than the step-growth process. State true or false.

A. true
B. false
Answer» C.
29.

Which of the following reaction is not accompanied by elimination of a byproduct molecule?

A. addition polymerization
B. condensation polymerization
C. both of the mentioned
D. none of the mentioned
Answer» B. condensation polymerization
30.

The substance that is so effective, which can suppress the rate as well as degree of polymerization is a ___________

A. retarder
B. inhibitor
C. promoter
D. none of the mentioned
Answer» C. promoter
31.

Which mode in the chain termination step is accompanied by a transfer of hydrogen molecule?

A. combination
B. disproportionation
C. propagation
D. all of the mentioned
Answer» C. propagation
32.

Which is the rate determining step of chain initiation step?

A. initiator decomposition
B. chain initiation of monomer
C. chain propagation
D. none of the mentioned
Answer» B. chain initiation of monomer
33.

What does chain initiation step of free radical polymerization consists of?

A. decomposition of initiator
B. addition of free radical to monomer
C. all of the mentioned
D. none of the mentioned
Answer» D. none of the mentioned
34.

Which of the following cannot initiate the chain reaction in polymerization of acrylo-nitrile?

A. anion
B. anion
C. free radical
D. coordination
Answer» C. free radical
35.

Why is addition polymerization also known as vinyl polymerization?

A. monomers are unsaturated compounds
B. its a chain reaction
C. most monomers contain (CH2═CH─) group
D. all of the mentioned
Answer» D. all of the mentioned
36.

Which of the following monomers cannot undergo chain growth polymerization?

A. CH2═ CH2
B. CH2═CHCN
C. CH2═CHCOOR
D. COOH−CH2−COOH
Answer» E.
37.

Which of the following can activate chain initiation?

A. heat
B. light or radiation
C. catalysts
D. all of the mentioned
Answer» E.
38.

How many times is the lighter period shorter than the darker one, if the steady state rate is one third of the average rate for very fast blinking?

A. 4
B. 8
C. 2
D. 3
Answer» C. 2
39.

What is the relative rate of polymerization, under steady conditions to that of slow blinking, when the dark period is 4 times longer than the light period?

A. 1/4
B. 1/5
C. 1/51/2
D. 1/2
Answer» C. 1/51/2
40.

Which of the following is correct regarding the proportionality of average rate for intensity of illumination, if there is very fast blinking with equal light and dark periods?

A. ( Rp) α ½ (I0)1/2( Rp) α ½ (I0)1/2
B. ( Rp) α (I0/2)1/2
C. ( Rp) α (I0)1/2
D. ( Rp) α 2(I0)1/2
Answer» C. ( Rp) α (I0)1/2
41.

What is the proportionality order for the average rate of polymerization for steady conditions and continuous illumination, with respect to intensity of illumination?

A. ½
B. 1
C.
D. -1
Answer» B. 1
42.

What is the intensity received by the system in rotating sector technique, under the limiting case of very fast flashing?

A. I0
B. I0/2
C. 2I0
D. 3I0
Answer» C. 2I0
43.

How is the average lifetime of a growing radical, under steady state, in a radical polymerization, defined?

A. ratio of the steady state radical concentration and the rate of its termination
B. ratio of termination of the radical and its steady state concentration
C. ratio of steady state radical concentration and the rate of propagation
D. cannot be determined
Answer» B. ratio of termination of the radical and its steady state concentration