

MCQOPTIONS
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, |
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. |
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- |
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. | -½ |
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 | |