Question

Phosphorus has three allotropic forms — (i) white phosphorus (ii) red phosphorus and (iii) black phosphorus. Write the difference between white and red phosphorus on the basis of their structure and reactivity.

Answer 1

a) • White phosphorus is discrete tetrahedral molecule. Thus it has tetrahedral structure with six P–P bonds. 

• Red phosphorus has polymeric structure in which P₄ tetrahedra are linked together through P—P bonds to form chain. 

(b) Reactivity 

White phosphorus is much more reactive than red phosphorus. This is because in white phosphorus there is angular strain in P₄ molecules because the bond angles are only of 60°.