Answer: None of the given options show polymer made up of H₂C=CH-CN (Acrylonitrile).
Explanation: Acrylonitrile (H₂C=CH-CN) which is a monomer on self linkage results in a large chain polymer called as
Polyacrylonitrile.
The structure of Polyacrylonitrile is as follow,
--(H₂C-CHCN-)n--Where n shows the number of Acrylonitrile units joined together in the formation of Polyacrylonitrile. This polymerization reaction can take place by different mechanisms including free radical mechanism, acid catalyzed addition or base catalyzed addition reaction.
The polymerization is shown below,
heating is repeated to ensure all water molecules have evaporated

so:



so:

it means that
in

of acid there is

moles of acid

so:

it means that:
in

of water there is

moles of water
therefore:

So your answers are:

and the mole fraction is:
3 bc Hf is an element hafnium and HF is compound hydrogen flouride