Question

The formula for the monomeric unit of PVC is:
A. \[C{H_3} - C{H_2} - C{H_2} - Cl\]
B. $C{H_2} = CH - C{H_2} - Cl$
C. $C{H_2} = CH - Cl$
D. $C{H_3} - CH = CH - Cl$

Answer 1

Hint: The large molecule made by the numerous repeating units is known as polymers. The simplest repeating unit in the structure of the polymer is known as monomer. The molecular mass of the polymers is very high, due to the nth number of monomer units present in the polymers.

Complete answer:
> The World’s third largest produced polymer is PVC that is Poly Vinyl Chloride, every year around 40 million tons of PVC is produced. The two basic forms of PVC are flexible and rigid. In the construction of the pipes and in applications such as in doors and windows the rigid form of the PVC is used. While the flexible form is used in other applications. PVC is white and brittle solid and is insoluble in alcohol. 

> The formula of the PVC is ${[C{H_2} - CH - Cl]_n}$, where n is the number of the monomer units combined or attached in the structure of the PVC molecule. The monomers in PVC are usually arranged in the head-to-tail fashion, thus the chlorides are there on the alternative carbon atoms and the stereochemistry of the chlorine atoms in them is random. Around 57% of the PVC is chlorine. The presence of the chlorine in the PVC gives it entirely different properties.
The process of the formation of the polymer from the monomer unit is known as Polymerisation. The monomer of PVC is Vinyl chloride. The formula of the vinyl chloride is $[C{H_2} = CH - Cl]$. 

> The polymerisation of the PVC molecule can be shown by the following reaction:
$n[C{H_2} = CH - Cl]\xrightarrow{{Polymerisation}}{[ - C{H_2} - CH - Cl - ]_n}$

So, the correct answer is Option C.

Note: The PVC is chemically inert to all the acids, salts and bases and thus is resistant to the corrosive nature of the effects of the sewage as well. Thus due to this very property it is extensively used in the sewer pipe lines. The PVC is also resistant to some other solvents as well.