Question

The correct statement is:

• A. Low reactivity of red phosphorus is due to polymeric structure
• B. Black phosphorus conducts electricity due to presence of delocalized electrons
• C. All the above
• D. High reactivity of white phosphorus is due small bond angle (60 degree) in P4 molecule which causes large strain

Answer 1

Answer: (C)

1.) The tetrahedral arrangement of white phosphorus results in ring strain and instability. The molecule consisting of six single P–P bonds. you can search the structure of both phosphorus and see that white phosphorus have tetrahedral while red phosphorus combines white other phosphorus structure and get rid of one single P-P bond.

2.) This high angular strain makes white phosphorus unstable and highly reactive. White phosphorus is made up of discrete $P_4$ tetrahedra which are subjected to very high angular strain as the angles are 60 degrees. Red phosphorus is a polymer of $P_4$ tetrahedra, which has much less angular strain.

3.) Delocalized electrons are electrons in a molecule, ion or solid metal that are not associated with a single atom or a covalent atom.

Materials with a band gap, known as “semiconductors,” are a special group of materials that only conduct electricity when the electrons in that material absorb enough energy for them to “jump” the bandgap. This means that black phosphorus can be tuned to absorb light in the visible range but also the infrared.

Hence, the correct option is $\text{D}$