Question

The monomer involved in the formation of polystyrene is

• A. \(CH_2=CH-Cl\)
• B. \(CH_2=CH-CN\)
• C. \(CH_2=CH-C_6H_5\)
• D. \(CH_2=CH-CH_3\)

Hint:

Many common polymer names are simply the prefix "poly-" added to the name of the monomer.
For example: poly(ethene), poly(propene), poly(styrene), poly(vinyl chloride).
Recognizing this naming convention can help you quickly identify the monomer.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
We need to identify the chemical structure of the monomer unit that polymerizes to form polystyrene.

Step 2: Key Formula or Approach:
The name "polystyrene" indicates that it is a polymer ("poly-") made from the monomer "styrene".
We need to know the structure of styrene. Styrene is also known as vinylbenzene or phenylethene.
It consists of a vinyl group (\(-CH=CH_2\)) attached to a phenyl group (a benzene ring, \(C_6H_5\)).

Step 3: Detailed Explanation:
Let's analyze the chemical structures given in the options:
-

(A) \(CH_2=CH-Cl\): This is vinyl chloride, the monomer for polyvinyl chloride (PVC).
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(B) \(CH_2=CH-CN\): This is acrylonitrile, the monomer for polyacrylonitrile (PAN), used in fibers like Orlon.
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(C) \(CH_2=CH-C_6H_5\): This is styrene (vinylbenzene). The addition polymerization of this monomer across the double bond results in polystyrene.
-

(D) \(CH_2=CH-CH_3\): This is propene (or propylene), the monomer for polypropylene.
Therefore, the correct monomer for polystyrene is styrene, \(CH_2=CH-C_6H_5\).

Step 4: Final Answer:
The monomer involved in the formation of polystyrene is \(CH_2=CH-C_6H_5\).