Pyridine is an organic compound having molecular formula [tex]C_{5}H_{5}N[/tex] and hydrogen chloride has the chemical formula [tex]HCl[/tex].
In structure of pyridine, nitrogen is attached with one of the carbons present in the benzene ring.
Now, when pyridine reacts with hydrogen chloride results in the formation of pyridinium chloride. In this reaction, hydrogen form bond with nitrogen due to the lone pair present on the nitrogen and gives +1 charge on the nitrogen with negative charge on chlorine.
The complete reaction is shown in the image.
