Chemistry MCQ help please

I can’t give the whole question sorry idk how to upload it but the answer says that a halogenoalkane undergoes addition polymerisation which i don’t think is correct and also that the reaction of this halogenoalkane with sodium cyanide followed by hydrolysis of the resulting product gives a carboxylic acid is incorrect. I thought this would happen. If someone could explain that’d be great, thanks.

I can’t give the whole question sorry idk how to upload it but the answer says that a halogenoalkane undergoes addition polymerisation which i don’t think is correct and also that the reaction of this halogenoalkane with sodium cyanide followed by hydrolysis of the resulting product gives a carboxylic acid is incorrect. I thought this would happen. If someone could explain that’d be great, thanks.

I can’t give the whole question sorry idk how to upload it but the answer says that a halogenoalkane undergoes addition polymerisation which i don’t think is correct and also that the reaction of this halogenoalkane with sodium cyanide followed by hydrolysis of the resulting product gives a carboxylic acid is incorrect. I thought this would happen. If someone could explain that’d be great, thanks.

Halogenoalkanes do not undergo polymerisation - there would have to be other functional groups on the molecule for that to be a possibility. Addition polymerisation requires there to be isolated C=C bonds present in the molecule (e.g think alkenes).
If a haloalkane reacts with NaCN, it gives a nitrile. Nitriles can be hydrolysed one of two ways:
(1) Heating under reflux with an aqueous strong acid, which produces a carboxylic acid, plus an ammonium salt as a co-product.
(2) Heating under reflux with an aqueous strong base, which produces a carboxylate salt, plus ammonia as a co-product. The carboxylate salt can be converted to a carboxylic acid upon the introduction of a strong acid.
I’d need to see the full question and your rationale to understand what the problem is with the second question.