Question

Give reason for the following:

Red phosphorus is less reactive than white phosphorus.

Assign appropriate reason for the following observation:

White phosphorus is much more reactive than red phosphorus.

Explain why:

Red phosphorus is less reactive than white phosphorous.

Answer 1

1. The presence of angular strain in any molecule can make it reactive. Such angular strain is found in the white phosphorous P₄ molecule, where the angles are only 60°, making it more reactive.
2. Also, white phosphorus is made of discrete tetrahedral P₄ molecules, while red phosphorus consists of chains of P₄ tetrahedra linked together.

Hence, on the basis of these facts, it can be concluded that red phosphorus is less reactive than white phosphorus.

Answer 2

This is because, in red phosphorus, there are strong covalent bonds in P₄ molecules, but in white phosphorus, there are Van der Waals forces of attraction in P₄ molecules.