Question

Which allotrope of phosphorus is also called yellow phosphorus?

(a) Black phosphorus

(b) Red phosphorus

(c) Beta- black phosphorus

(d) White phosphorus

The question was posed to me by my school principal while I was bunking the class.

This intriguing question originated from P-Block Elements in division P-Block Elements of Chemistry – Class 12

Answer 1

The correct answer is (d) White phosphorus

Easiest explanation: White phosphorus on exposure to light, it turns yellow. It glows greenish in the dark (when exposed to oxygen) and is highly flammable and pyrophoric (self-igniting) upon contact with air. Therefore it is called yellow phosphorus.