Question

why black Phosphorus has least reactivity!​

Answer 1

$\huge{\underline{\mathscr{\purple{Hey, mate....!!!}}}}$

$\huge{\red{\mathfrak{ANSWER:-}}}$

Black phosphorus is the most stable allotrope of phosphorus, so it must have the leastangular strain. Black phosphorus has an orthorhombic structure and is the least reactive allotrope, a result of its lattice of interlinked six-membered rings where each atom is bonded to three other atoms.

Answer 2

Answer:

Black phosphorus is the thermodynamically stable form of phosphorus at room temperature and pressure, with a heat of formation of -39.3 kJ/mol (relative to white phosphorus which is defined as the standard state).[1] It is obtained by heating white phosphorus under high pressures (12,000 atmospheres).  

Black phosphorus has an orthorhombic structure and is the least reactive allotrope, a result of its lattice of interlinked six-membered rings where each atom is bonded to three other atoms.

credits : class 12 NCERT

                class 12 SChand