Question

Red phosphorus is chemically unreactive because

• A. it does not contain $P-P$ bonds
• B. it does not contain tetrahedral $P_4$ molecules
• C. it does not catch fire in air even upto $400^{\circ }C$
• D. it has a polymeric structure.

Answer 1

Answer: (D)

In red phosphorus, one of the $P_4$ bonds is broken, and one additional bond is formed with a neighbouring tetrahedron resulting in a more chain-like structure.

It is formed by heating white phosphorus to $250^{\circ }C$, it becomes an amorphous network of atoms that reduces strain and gives greater stability thereby renders it unreactive.