Question

Given below are four statements regarding the allotropes of phosphorus. Which of them is/are incorrect?

• A. White Phosphorus is a waxy, molecular solid that has a garlic-like odour
• B. Red Phosphorus is more reactive than white phosphorus and it is soluble in carbon disulphide
• C. Red Phosphorus can be cut with a knife
• D. Red Phosphorus is a non-toxic, odourless polymeric solid at room temperature

Answer 1

Answer: (B), (C)

The correct options are
B Red Phosphorus is more reactive than white phosphorus and it is soluble in carbon disulphide
C Red Phosphorus can be cut with a knife

First, let us get the correct ones out of the way and then the reason to why the rest are incorrect?
You will encounter some strange odours associated with white phosphorus (garlic-like odour).

White phosphorus is a waxy solid at room temperature and so it can be cut with a knife. It melts close to ${30}^{\circ }C$ which makes white phosphorus much more reactive than its red counterpart. Red Phosphorus is a hard, odourless, non-toxic, polymeric solid which cannot be cut with an everyday kitchen knife.