Tag: polymer

Questions Related to polymer

Arrange the following types of polymer in order of decreasing force of attraction.


   Fibres        Elastomer                Thermoplastic
      (I)                 (II)                               (III)

classification of polymers introduction to polymers and its classification polymer polymers chemistry

  1. I > II > III

  2. I > III > II

  3. II > I > III

  4. III > II > I

Show answer
Correct Option: B
Explanation:

Fiber have strong intermolecular forces of attraction take H-bonding.


Elastomers have weak fores of attraction which thermoplastic have weakest 
forces like london or dispersion forces / vanderwaal forces.

So order is $(I)>(III)>(II)$

Which monomer would polymerise in isotactic, syndiotactic and atactic forms ?

classification of polymers introduction to polymers and its classification polymer polymers chemistry

  1. $CH _2 = CCl _2$

  2. $CH _3-CH=CH _2$

  3. $Ph-CH=CH _2$

  4. All of the above

Show answer
Correct Option: B,C

Which pair of polymers have similar properties?

classification of polymers introduction to polymers and its classification polymer polymers chemistry

  1. Nylon, $PVC$

  2. $PAN, PTFE$

  3. $PCTFE, PTFE$

  4. Bakelite, alkyle resin

Show answer
Correct Option: C
Explanation:

$PCTFE, PTFE$ both have same carbon backbone

  1. $-[ClFC - CF _{2}] _{n}$ $ = PCTFE$ (polymonochloro tetrafluoro ethylene)
  2. $ [F _{2}C - CF _{2}] _{n} = PTFE$ (polytetrafluoro ethylene).

Determine the degree of association (polymerization) for the reaction in aqueous solution
$6HCHO\rightleftharpoons C _6H _{12}O _6$
If observed (mean) molar mass of HCHO and $C _6H _{12}O _6$ is $150$.

chemistry polymer addition polymerisation types of polymerisation reactions petrochemicals and polymers

  1. $0.50$

  2. $0.833$

  3. $0.90$

  4. $0.96$

Show answer
Correct Option: D
Explanation:
Let us consider the problem.
$\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, 6HCHO \,\,\,\,\,\leftrightarrow {C _6}{H _{12}}{O _6}$
At equation $c\left( {1 - \alpha } \right)\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\dfrac{{C\alpha }}{6}$
$\dfrac{{Observed\,moles\,concentration}}{{Initial\,moles\,concentration}} = \dfrac{{{M _\gamma }}}{{{M _0}}}$
$\dfrac{{C\left( {1 - \alpha } \right) + \dfrac{{C\alpha }}{6}}}{C} = \dfrac{{{M _\gamma }}}{{{M _0}}} = \dfrac{{30}}{{150}}$
Hence the answer is $\alpha  = 0.96$

The monomer that undergo radical polymerisation most easily is ?

chemistry polymer addition polymerisation types of polymerisation reactions petrochemicals and polymers

  1. $CH _2=CH _2$

  2. $C _6H _5CH=CH _2$

  3. $CH _2=C{(Me)} _2$

  4. $CH _3-CH=CH _2$

Show answer
Correct Option: A

During the vinyl polymerisation, the chain transfer agent is:

chemistry polymer addition polymerisation types of polymerisation reactions petrochemicals and polymers

  1. $C{Cl} _{4}$

  2. ${C} _{6}{H} _{5}OH$

  3. t-butyl peroxide

  4. diphenylamine

Show answer
Correct Option: A
Explanation:
In the presence of $C{Cl} _{4}$ or any other chain transfer agents, the monomer polymerizes to give lower average molecular mass polymers.
Hence, the correct option is A.

Which one of the following polymer is step-growth polymer

chemistry polymer addition polymerisation types of polymerisation reactions petrochemicals and polymers

  1. Polythylene

  2. Nylon-$66$

  3. Buna-$S$ rubber

  4. Orlon

Show answer
Correct Option: A

Which of the following free radicals is the most stable ?

chemistry polymer addition polymerisation types of polymerisation reactions petrochemicals and polymers

  1. primary

  2. methyl

  3. secondary

  4. tertiary

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Correct Option: D
Explanation:

Electron poor species are stabilized by neighboring atoms that can donate electron density. The most common way to interpret rich neighbors here is the observation that increasing the number of alkyl groups on the carbon bearing the free radical increases its stability. 


Radical stability increases in the order methyl < primary < secondary < tertiary. 

Hence, option $D$ is correct.

Which of the following polymer is not an addition polymer?

chemistry polymer addition polymerisation types of polymerisation reactions petrochemicals and polymers

  1. Teflon

  2. BUNA-N

  3. PAN

  4. Propylene

Show answer
Correct Option: B
Explanation:

BUNA-N is formed by removal of water molecule so it is condensation polymer.

Which of the following are used as free radical chain initiators ?

chemistry polymer addition polymerisation types of polymerisation reactions petrochemicals and polymers

  1. Benzoyl peroxide

  2. di-tert-butyl peroxide

  3. Carbon tetrachloride

  4. Benzoquinone

Show answer
Correct Option: A,B
Explanation:

A radical initiator is a species that acts as the reactant of the initiation step of a radical chain reaction but does not participate in any of the propagation steps.
Radical initiators are substances that can produce radical species under mild conditions and promote radical reaction. These substances generally possess weak bonds that have small bond dissociation energy. Radical initiators are utilized in industrial processes such as polymer synthesis. Typical examples are halogen molecules, azo compounds and organic and inorganic peroxides such as Benzoyl peroxide, di- t-Butyl peroxide.