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Synthetic rubber - class-VIII

Description: synthetic rubber
Number of Questions: 22
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Tags: polymer manmade materials polymers chemistry
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Heating rubber with sulphur is known as:

chemistry manmade materials synthetic rubber rubber polymer

  1. galvanization

  2. bessemerisation

  3. vulcanization

  4. sulphonation

Show answer
Correct Option: C
Explanation:

The formation of vulcanised rubber-

To improve these physical properties,
  • water repelent
  • Less water absorption
  • Resist for oxidising agents
  • Strength
 a process of vulcanisation is carried out. This process consists of heating a mixture of raw rubber with sulphur and an appropriate additive at a temperature range between 373 K to 415 K.On vulcanisation, sulphur forms cross links at the reactive sites of double bonds and thus the rubber gets stiffened, The correct option is [C].

In vulcanization of rubber :

chemistry manmade materials synthetic rubber rubber polymer

  1. sulphur reacts to form a new compound

  2. sulphur cross-links are introduced

  3. sulphur forms a very thin protective layer over rubber

  4. all statements are correct

Show answer
Correct Option: B
Explanation:

Vulcanisation of rubber-

To improve these physical properties,
  • Strength
  • Resistance for oxidation
  • Repulsion from water
 a process of vulcanisation is carried out. This process consists of heating a mixture of raw rubber with sulphur and an appropriate additive at a temperature range between $373 K to 415 K.$ On vulcanisation, sulphur forms cross links at the reactive sites of double bonds and thus the rubber gets stiffened.

The correct option is [B].

Sulphur is used in  the vulcanization of rubber.

chemistry polymer synthetic rubber rubber manmade materials

  1. True

  2. False

Show answer
Correct Option: A

Vulcanization of rubber helps to make rubber hard and resistant to hot and cold conditions.

chemistry polymer synthetic rubber rubber manmade materials

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

Vulcanization is a process in which the strength, stability, and elasticity of rubber are increased by subjecting it to heat, in the presence of sulphur. As a result, cross-linking occurs between the chains of rubber molecules and sulphur atoms.

The process involving heating of rubber with sulphur is called ___

chemistry manmade materials synthetic rubber rubber polymer

  1. Galvanisation

  2. Vulcanization

  3. Bessemerisation

  4. Sulphonation

Show answer
Correct Option: B
Explanation:

Vulcanisation of Rubber - Natural rubber  becomes soft at high temperature (>$335$ K) and brittle at low temperature (<$283$ K) and shows high water absorption capacity.
The process of  vulcanisation includes heating of raw rubber with sulphur and an appropriate additive at temperature range between $373$ K  to $415$ K. Sulphur foms crosslinks at reactive sites of double bonds and thus, rubber gets stiffened.

The synthetic polymer which resembles natural rubber is:

chemistry manmade materials synthetic rubber rubber polymer

  1. Neoprene

  2. Buna-S

  3. Nylon

  4. Rayon

Show answer
Correct Option: A
Explanation:

Neoprene resembles natural rubber. 


Natural rubber is a linear polymer of $2$-methyl-$1,:3$-butadiene called as isoprene and Neoprene is a linear polymer of $2$-chloro-$1,:3$-butadiene called as chloroprene.

Option A is correct.

Chloroprene is used in making

chemistry manmade materials synthetic rubber rubber polymer

  1. synthetic rubber

  2. plastic

  3. petrol

  4. All of the above

Show answer
Correct Option: A
Explanation:

Chloroprene is the monomer of neoprene, a synthetic rubber formed by the free radical polymerisation of choloroprene.


$nCH _2-CCl-CH=CH _2 \xrightarrow {Polymerisation} -[CH _2-CCl=CH-CH _2]-$

The process of vulcanization was introduced by ____

chemistry manmade materials synthetic rubber rubber polymer

  1. Charles Goodyear

  2. Kolbe

  3. Wohler

  4. Zeigher

Show answer
Correct Option: A
Explanation:

Charles Goodyear invented vulcanization process in $1839$.
Vulcanisation is a process involving heating of rubber with sulphur is called vulcanisation.

The tensile strength, elasticity and resistance to abrasion can be increased by a process called ___

chemistry manmade materials synthetic rubber rubber polymer

  1. Galvanisation

  2. Vulcanization

  3. Bessemerisation

  4. Sulphonation

Show answer
Correct Option: B

Which of the following is used in making automobile tyres and foot wear?

chemistry manmade materials synthetic rubber rubber polymer

  1. Vulcanised rubber

  2. Neoprene

  3. Plexi glass

  4. Glyptal

Show answer
Correct Option: A
Explanation:

Vulcanised rubber is used in making automobile tyres and foot wear. Heating of rubber with sulphur is called as vulcanisation. It makes the rubber hard and more flexible.

Vulcanization of rubber helps to make rubber hard and resistant to hot and cold conditions.

chemistry manmade materials synthetic rubber rubber polymer

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

Vulcanization of rubber is a chemical process used for converting natural rubber into more durable material by addition of sulphur.
Vulcanization of rubber helps to make rubber hard and resistant to hot and cold conditions. 

What percentage of sulphur is used in the vulcanization of rubber?

chemistry manmade materials synthetic rubber rubber polymer

  1. $5$%

  2. $3$%

  3. $30$%

  4. $55$%

Show answer
Correct Option: A
Explanation:

$5$% of sulphar is used in order to extent the stiffness of valcanised rubber.

Which of the following has cross-linked polymer?

chemistry manmade materials synthetic rubber rubber polymer

  1. Vulcanised rubber

  2. Nylon

  3. Phenol-formaldehyde resins

  4. Both $A$ and $C$

Show answer
Correct Option: D

In the process of vulcanization:

chemistry manmade materials synthetic rubber rubber polymer

  1. natural rubber is heated with sulphur

  2. natural rubber is heated with carbon

  3. natural rubber is heated with phosphorous

  4. natural rubber is heated with sodium

Show answer
Correct Option: A
Explanation:

Vulcanization is a chemical process by which the physical properties of natural or synthetic rubber are improved. In its simplest form, vulcanization is brought about by heating rubber with sulfur.

Which material is used for vulcanisation of rubber?

chemistry manmade materials synthetic rubber rubber polymer

  1. Iron

  2. Sulphur

  3. Chlorine

  4. Calcium Carbonate

Show answer
Correct Option: B
Explanation:

The material used for the vulcanisation of rubber is sulphur.


The reasons why the rubber is vulcanised are as follows:

i) It is soft and sticky and becomes more so at high temperature and brittle at low temperature. That is why, it is used at low-temperature range ($280-330$) K, where its elasticity is maintained.
ii) It is attacked by oxygen and other oxidising agents.
iii) It has a high water absorption capacity, low tensile strength and low resistance to abrasion.
iv) It is reactive to organic solvents.
Therefore, natural rubber is vulcanised by heating it with about ($3-5\%$) sulphur at ($373-415$) K.

Strength of synthetic fibre is better during-

chemistry manmade materials synthetic rubber rubber polymer

  1. dry condition

  2. wet condition

  3. humid condition

  4. never

Show answer
Correct Option: A

Which of the following type of forces are present in vulcanized rubber?

chemistry manmade materials synthetic rubber rubber polymer

  1. Weakest intermolecular forces

  2. Hydrogen bonding

  3. Three dimensional network of bonds

  4. Metallic bonding

Show answer
Correct Option: A
Explanation:

Vulcanised rubber is highly elastic, so weakest intermolecular forces present in it.

Which of the following is resistant to petrol, lubricating oils and organic solvents?

chemistry manmade materials synthetic rubber rubber polymer

  1. Nitrile rubber

  2. Buna - N

  3. GRN

  4. All of these

Show answer
Correct Option: D

A : A mixture of raw rubber and sulphur on heating at $373:K$ - $415:K$ gives vulcanised rubber.
R : ZnO decreases the rate of vulcanisation of rubber.

chemistry manmade materials synthetic rubber rubber polymer

  1. both A and R are correct and R is the correct explanation of the A

  2. both A and R are correct but R is not the correct explanation of the A

  3. A is correct but R is incorrect

  4. A is incorrect but R is correct

Show answer
Correct Option: C
Explanation:
Natural rubber becomes soft at high temperature (>335 K) and brittle at low temperatures (<283 K) and shows high water absorption capacity. It is soluble in non-polar solvents and is non-resistant to attack by oxidising agents. 

To improve upon these physical properties, a process of vulcanisation is carried out. This process consists of heating a mixture of raw rubber with sulphur and an appropriate additive at a temperature range between 373 K to 415 K. On vulcanisation, sulphur forms cross links at the reactive sites of double bonds and thus the rubber gets stiffened.

In sulfur vulcanization of natural rubber, the types of cross-links formed largely depend on the vulcanization system. The vulcanizing agents are zinc oxide (ZnO), stearic acid, accelerators, and sulfur. Conventional ZnO, or micro ZnO, is one of the basic components of rubber compounds and acts as an activator for rubber crosslinking by sulfur or sulfur donors.

Hence, reason given is incorrect. So, option C is correct.

Assertion (A) : The plants yield a milky suspension of crude rubber called latex.
Reason (R) : The latex contains about $85\%$ rubber.

chemistry manmade materials synthetic rubber rubber polymer

  1. Both A and R are correct and R is the correct explanation of the A

  2. Both A and R are correct but R is not the correct explanation of the A

  3. A is correct but R is incorrect

  4. A is incorrect but R is correct

Show answer
Correct Option: C
Explanation:
The plants yield a milky suspension of crude rubber called latex.
Latex is often described as the sap of the Hevea tree, a milky sticky substance. 

The sap runs deeper inside the tree, beneath the cambium.
Latex runs in the latex ducts which are in a layer immediately outside the cambium. This highlights the skill of the tapper. 

If the cambium is cut, then the tree is damaged because the cambium is where all the growth takes place.

The latex contains about $60\%$ of rubber and $40\%$ of other substances (water, proteins etc).


Assertion (A) is correct. Reason (R) is incorrect. Option C is correct.

Acetaldehyde can be used for making synthetic:

chemistry manmade materials synthetic rubber rubber polymer

  1. protein

  2. perfumes

  3. rubbers

  4. sugar

Show answer
Correct Option: C
Explanation:

Acetaldehyde is primarily used as an intermediate in the manufacture of a range of chemicals, perfumes, aniline dyes, plastic and synthetic rubber, etc.

$\therefore$ Answer is option $B$ and $C$.

Which of the following is not a synthetic rubber?

chemistry manmade materials synthetic rubber rubber polymer

  1. Neoprene

  2. Buna-N rubber

  3. Buna-S rubber

  4. Polyethylene

Show answer
Correct Option: D
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