Tag: chemistry

Questions Related to chemistry

Which of the following is added to improve flexibility of PVC?

chemistry petrochemicals and polymers addition polymerisation types of polymerisation reactions polymer

  1. Rubber

  2. Plasticizers

  3. Ethane

  4. Flexicizers

Show answer
Correct Option: B
Explanation:

With some additives in PVC, the physical and mechanical properties are improved.

Different additives such as plasticizers, fillers, stabilizer, pigments were mixed. These are added in order to increase the elongation i.e; its flexibility.

Which is used in making various types of pipes?

chemistry petrochemicals and polymers addition polymerisation types of polymerisation reactions polymer

  1. PVR

  2. PVC

  3. Bakelite

  4. Melamine

Show answer
Correct Option: B
Explanation:
PVC (polyvinyl chloride) is used in making various types of pipes.
Note: PVC thermoplastic polymer. Its properties are between elastomers and fibers. On heating, it becomes soft and on cooling, become hard. It can be remoulded and recycled.

PVC is an example of which kind of plastic?

chemistry petrochemicals and polymers addition polymerisation types of polymerisation reactions polymer

  1. Thermoplastic

  2. Thermosetting

  3. It is not a type of plastic

  4. Both $A$ and $B$

Show answer
Correct Option: A
Explanation:

PVC (polyvinyl chloride) is thermoplastic polymer. Its properties are between elastomers and fibers. On heating, it becomes soft and on cooling, become hard. It can be remoulded and recycled.

Which of the following polymer has the tendency of decomposing before melting ?

chemistry petrochemicals and polymers addition polymerisation types of polymerisation reactions polymer

  1. Polystyrene

  2. PVC

  3. Nylon

  4. None of the above

Show answer
Correct Option: D
Explanation:
Thermosetting polymers such as Bakelite have the tendency of decomposing before melting. Thermoplastic polymers (such as PVC (polyvinyl chloride), polystyrene ) on heating, becomes soft and on cooling, become hard. They can be remolded and recycled. Their properties are between elastomers and fibers.
There is no thermosetting given in the option, all are thermoplastic.
Hence, the correct option is D.

In additional polymerization, a monomer with double bond will simply :

chemistry petrochemicals and polymers addition polymerisation types of polymerisation reactions polymer

  1. break

  2. remain same

  3. turn into the single bond

  4. none of the above

Show answer
Correct Option: C
Explanation:

$\text{Double bonds breaks of one monomer for addition with another monomer.}$

$F _2C = CF _2$ is a monomer of:

chemistry petrochemicals and polymers addition polymerisation types of polymerisation reactions polymer

  1. teflon

  2. glyptal

  3. nylon-6

  4. buna-S

Show answer
Correct Option: A
Explanation:

$F _2C=CF _2$ is a monomer of polytetrafluoroethylene also called as Teflon.

       $nF _2C=CF _2\longrightarrow -[F _2C-CF _2]- _n$
(Tetrafluoroethylene)    (Teflon Polytetrafluoroethylene)

In additional polymerization, unsaturated monomers contain :

chemistry petrochemicals and polymers addition polymerisation types of polymerisation reactions polymer

  1. single bond

  2. double bond

  3. both A and B

  4. triple bond

Show answer
Correct Option: B
Explanation:

Many common addition polymer are formed from unsaturated monomers having $C=C$ bond.

In condensation of polymerization, involves monomers which contain functional groups of:

chemistry petrochemicals and polymers addition polymerisation types of polymerisation reactions polymer

  1. same kind

  2. different kind

  3. all groups

  4. compounds

Show answer
Correct Option: B
Explanation:

Condensation polymers involves monomers which join together losing a small molecules as byproducts such as $H _2O$, methanol, etc.

Condensation polymers are formed from two or more different monomers.

Polymer formation from monomers starts by:

chemistry petrochemicals and polymers addition polymerisation types of polymerisation reactions polymer

  1. condensation reaction between monomers

  2. coordination reaction between monomers

  3. conversion of monomers to monomer ion by protons

  4. hydrolysis of monomers

Show answer
Correct Option: A
Explanation:

Polymer formation from monomers starts by condensation reaction between monomers by removal of small molecules.

Which of the following polymer type is not classified on the basis of its application and properties?
chemistry petrochemicals and polymers addition polymerisation types of polymerisation reactions polymer

  1. rubber

  2. plastic

  3. fibers 

  4. synthetic

Show answer
Correct Option: D
Explanation:

Synthetic polymers are classified on the basis of their origin and are known as man-made polymers.

Hence,
option $D$ is correct answer.