Identify the correct decreasing order of basic strength for the following compounds: (I) (II) (III) (IV) (V)

Step-by-step solution

The basic strength of nitrogenous compounds depends on the availability of the lone pair of electrons on the nitrogen atom for protonation. 1. Compound (II) is piperidine, a secondary aliphatic amine where the nitrogen atom is sp^3 hybridized. It has no electron-withdrawing groups, making its lone pair highly available. Thus, it is the most basic. 2. Compounds (IV) morpholine and (V) thiomorpholine are also secondary aliphatic amines but contain electronegative heteroatoms (oxygen and sulfur, respectively) at the 4