Which compound forms linear polymer due to \[H - \] bond:
A.\[{H_2}O\]
B.\[N{H_3}\]
C.\[HF\]
D.\[HCl\]

Hint: A linear polymer is a long continuous chain of carbon–carbon bonds with the remaining two valence bonds attached primarily to hydrogen or another relatively small hydrocarbon moiety.
Hydrogen bonding is a special type of dipole-dipole attraction between molecules, not a covalent bond to a hydrogen atom. It results from the attractive force between a hydrogen atom covalently bonded to a very electronegative atom such as a \[N\], \[O\], or \[F\] atom and another very electronegative atom.

Complete answer:
Option A:
In water, the molecules form an intermolecular \[H - \] bonding between hydrogen of one water molecule and oxygen of another water molecule. However, the shape of hydrogen bonding in water is not linear. The bonding is more like a zig-zag pattern. Therefore, option A is incorrect.
Option B:
In ammonia, the molecules form an intermolecular hydrogen bonding. It occurs between nitrogen of one molecule and hydrogen of another molecule. The bonding is continued in this manner and has a linear shape but it does not create polymers. Therefore, option B is incorrect.
Option C:
Hydrogen fluoride also forms intermolecular hydrogen bonding. The electronegativity of fluorine is very high and due to this, it forms effective hydrogen bonding. The shape of hydrogen fluoride is also linear. Therefore, option C is correct.
Option D:
Since, hydrogen bonding is only seen when a \[N\], \[O\], or \[F\] atom is involved, therefore there is no hydrogen bonding in hydrogen chloride. Therefore, option D is incorrect.
And hence option C is the correct answer.

Note:
Polymers can be grouped as linear polymers and branched polymers depending on their structures. The main difference between branched polymer and linear polymer is that branched polymers have a branched structure whereas linear polymers have a linear structure.
Hydrogen fluoride is a very strong acid and is a gas at room temperature. It is usually stored in plastic containers due to high reactivity towards glass.