Engineering Questions with Answers - Multiple Choice Questions

Applied Chemistry MCQ – Natural Rubber

1 - Question

The polymers which possess the property of elastic is called rubber.
a) True
b) False

View Answer

Answer: a
Explanation: The polymers which possess the property of elastic is called the rubber. Temporary deformation takes place.




2 - Question

The temporary deformation of rubber takes place after applying the _______ stress.
a) 600e.u
b) More than 600e.u
c) 500e.u
d) more than 500e.u

View Answer

Answer: b
Explanation: The temporary deformation of the rubber takes place after applying the stress around more than 600e.u. when the stress is applied the chains get partially aligns with respect to the other.




3 - Question

The elasticity of the rubber is due to its ___________
a) Trigonal planar
b) Octahedral
c) Pentagonal bipyramidal
d) Helix

View Answer

Answer: d
Explanation: The elasticity of the rubber is due to its helical structure. On releasing the stress, the chains get reverted back to their original coiled state.




4 - Question

Isoprene in natural rubber exists in ___________ geometrical isomeric forms.
a) 2
b) 3
c) 4
d) 5

View Answer

Answer: a
Explanation: Isoprene in natural rubber exists in two geometrical isomeric forms. They are cis-isoprene and trans-isoprene.




5 - Question

Cis-poly isoprene is present in ________
a) Hevea rubber
b) Guayule rubber
c) Percha rubber
d) Gutta rubber

View Answer

Answer: a
Explanation: Cis-poly isoprene is present in the Hevea rubber and the trans-poly isoprene is present in guayule rubber and percha rubber.




6 - Question

The latex is diluted to _________ and filtered to remove suspended impurities.
a) 5-10%
b) 10-15%
c) 15-20%
d) 20-25%

View Answer

Answer: c
Explanation: The latex is diluted to 15-20% and filtered to remove suspended impurities like pieces of bark, leaves etc.




7 - Question

The filtered latex is sent into the tanks and treated with __________
a) Acetic acid
b) Formaldehyde
c) Acetaldehyde
d) Poly isoprene

View Answer

Answer: a
Explanation: The filtered latex is sent into the tanks and treated with the acetic acid. Instead of acetic acid, sometimes we can also use the formic acid.




8 - Question

The rubber coagulates into soft _________ colour mass.
a) Yellow
b) Light yellow
c) White
d) Light pink

View Answer

Answer: c
Explanation: The rubber coagulates into soft white colour mass which is called as coagulam and then filtered and washed with water.




9 - Question

While producing the crepe rubber, the coagulam is passed between two rollers of about _________ wide.
a) 3mm
b) 4mm
c) 50cm
d) 100cm

View Answer

Answer: c
Explanation: The coagulam is passed in between the two rollers of about 3mm apart and 50cm wide and extruded in the form of a sheet which resemble the crepe paper, which possess rough surface.




10 - Question

While producing the smoked rubber, the filtered latex is fed into long rectangular tanks of _________ deep.
a) 1m
b) 2m
c) 50cm
d) 30cm

View Answer

Answer: d
Explanation: In one type of processing the filtered latex is fed into long rectangular tanks of 30cm deep and 1m wide




11 - Question

While producing smoked rubber, the latex and reacted with formic acid, the vertical partition plates are inserted and left undisturbed for _________
a) 13 hours
b) 14 hours
c) 15 hours
d) 16 hours

View Answer

Answer: d
Explanation: After introducing the latex and reacted with formic acid, the vertical partition plates are inserted and left undisturbed for 16 hours.




12 - Question

While producing the smoked rubber, the sheets are hanged for about _________ in smoked chambers.
a) 1 day
b) 2 days
c) 3 days
d) 4 days

View Answer

Answer: d
Explanation: While producing the smoked rubber, the sheets are hanged for about 4 days in smoked chambers. The final roller gives ribbed pattern to the rubber sheet.




13 - Question

To produce the smoked rubber, the rubber sheets are hanged in smoked chambers at __________
a) 10-20oC
b) 20-30oC
c) 30-40oC
d) 40-50oC

View Answer

Answer: d
Explanation: To produce the smoked rubber, the rubber sheets are hanged in smoked chambers at 40-50oC for four days.




14 - Question

Solvent extraction process is used to extract __________
a) Crepe rubber
b) Smoked rubber
c) Gutta percha
d) Guayule rubber

View Answer

Answer: c
Explanation: Solvent extraction process is the method of extracting the gutta percha. It is extracted from the matured leaves of the palagum gutta and dichopsis gutta.




15 - Question

 In solvent extraction process, the mature leaves are grounded and heated about _________
a) 40oC
b) 50oC
c) 60oC
d) 70oC

View Answer

Answer: d
Explanation: In solvent extraction process, the mature leaves are grounded and heated about 70oC. It is heated along with water.

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