White phosphorus exists as

Options

A. `P_(8)` molecules
B. `P_(4)` molecules
C. `P_(2)` molecules
D. `P_(6)` molecules

Answer

2

Explanation

White phosphorus , a solid at room temperature is soft, waxy and reactive. It exists as tetrahedral `P_(4)` molecules, and the tetrahedral structure remains in the liquid and gaseous state. Above `800^(@)C P_(4)` moleculesin the gas begin to dissocaite into `P_(2)` which have a bond enthalpy of `489.6" kJ mol"^(-1)`. This is only half the value for`N equiv N` because the orbitals in the third shell are much large and give relatively poor `p_(pi)-p_(pi)` overlap.