although Chlorine has same electronegativity as nitrogen.It does not formhydrogen bonding why?

Answer 1

Chlorine is a much larger atom, and therefore its electron cloud is distributed over a wider surface area, so its electron density is not as dense as nitrogen's, especially when bonded to something like carbon. HCl molecules, when pure, will hydrogen bond to themselves, or to other gases in a mixture, and when dissolved in water and separated into H+ and Cl- the Cl- will make transient hydrogen bonds to the hydrogens in water. They're just not very strong, because chlorine is pretty big compared to nitrogen.

Answer 2

Lancenigo di Villorba (TV), Italy

Why you think that?
Anhydrous hydrochloric acid, that is pure compound, is a gas whole molecules interact among themselves by secondary chemical bonds. The latters are known as "hydrogen bonds", since hydrogen atoms are bound to chlorine's ones which are electronegative atoms (see Pauling's electronegativity).
An english scientist of XIX century (the chemist sir Williamson) purposed an analogous interpretation (except electronegativity's conception) of behaviour of hydrogen and chlorine's atoms mutually bound in HCl's molecule.

I hope this helps you.