Question

Which allotrope of phosphorus is the most reactive?

• A. White phosphorus
• B. $\alpha$-Black phosphorus
• C. Red phosphorus
• D. $\beta$-Black phosphorus

Answer 1

The correct option is A White phosphorus

The three allotropic forms of phosphorus differ widely in their chemical reactivity in which white phosphorus is the most reactive while black and red phosphorus are less reactive.
White phosphorus is made up of discrete $P_4$ tetrahedra which is subjected to very high angular strain as the angle is ${60}^{\circ }$. This high angular strain makes white phosphorus unstable and highly reactive.