The reaction of amines with mineral acids to form ammonium salts shows that these are basic in nature. Amines have an unshared pair of electrons on the nitrogen atoms due to which they behave as Lewis bases. The basicity of amines is related to their structure. The basic character of an amine depends upon the ease of formation of a cation by accepting a proton from the acid. The more stable the cation is relative to the amine, the more basic the amine.

Structure of ammonium salt when ethylamine reacts with one mole of HCl?

C₂H₅—NH₃⁺_Cl⁻

When ethyl amine reacts with HCl, it forms ethyl ammonium chloride as a product.