The correct order of increasing intermolecular hydrogen bond strength is

The correct order of increasing ionic radii is

The gas produced by treating an aqueous solution of ammonium chloride with sodium nitrite is :

Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R.

Assertion A : Fluorine forms one oxoacid.

Reason R : Fluorine has smallest size amongst all halogens and is highly electronegative.

In the light of the above statements, choose the most appropriate answer from the options given below :