Which of the following describes a primary amine?

Study for the Medical Chemistry Test. Explore multiple choice questions with hints and explanations. Get exam-ready with engaging quizzes and comprehensive study materials.

A primary amine is defined by a nitrogen atom bonded to exactly one carbon-containing group and two hydrogens. This gives the neutral amine structure with three sigma bonds (one N–C and two N–H) and a lone pair. The description of nitrogen attached to one alkyl group and two hydrogens fits this perfectly. If there were two carbon substituents and one hydrogen, it would be a secondary amine; three carbon substituents would be a tertiary amine; four carbon substituents would form a quaternary ammonium species, which carries a positive charge and has no lone pair.