• The nitrogen atom in ammonia and amine molecules can?accept?a?proton?(H⁺?ion)
• They can therefore act as?bases?in aqueous solutions by?donating?its lone pair of electrons to a proton and form a?dative bond
  • For example, ammonia undergoes an?acid-base?reaction with dilute hydrochloric acid (HCl) to form a salt

NH₃?+ HCl → NH₄⁺Cl^-

^{base????? acid??????????? salt}

The nitrogen atom in ammonia and amines can donate its lone pair of electrons to form a bond with a proton and therefore act as a base

Strength of ammonia and amines as bases

• The?strength?of amines depends on the?availability?of the lone pair of electrons on the nitrogen atom to form a dative covalent bond with a proton
• The?more readily?this lone pair of electrons is available, the?stronger the base?is
• Factors that may affect the?basicity?of amines include:
  • Positive inductive effect?- Some groups such as?alkyl groups?donate electron density to the nitrogen atom causing the lone pair of electrons to become more available and therefore?increasing?the amine’s?basicity
  • Delocalisation?- The presence of aromatic rings such as the?benzene ring?causes the lone pair of electrons on the nitrogen atom to be?delocalised?into the benzene ring
  • The lone pair becomes?less available?to form a dative covalent bond with ammonia and hence?decreases?the amine’s?basicity
• For example, ethylamine (which has an electron-donating ethyl group) is?more basic?than?phenylamine?(which has an electron-withdrawing benzene ring)