The most thermodynamically stable allotropic form of phosphorus is _____.A) RedB) WhiteC) BlackD) Yellow

The most thermodynamically stable allotropic form of phosphorus is C) Black phosphorus.

Explanation:
Phosphorus has several allotropes, which are different structural forms of the same element. The main allotropes of phosphorus are:

White phosphorus: This is the most reactive form of phosphorus. It consists of P₄ tetrahedra and is highly unstable in air, often igniting spontaneously. Due to its high reactivity, it is not thermodynamically stable.

Red phosphorus: This form is more stable than white phosphorus and is less reactive. It has a network structure and does not ignite in air at room temperature, but it is still not the most stable allotrope.

Black phosphorus: This allotrope has a layered structure similar to graphite. It is the least reactive of the phosphorus allotropes and exhibits properties such as electrical conductivity. Black phosphorus is the most thermodynamically stable form because it has a lower energy state compared to the other allotropes.

Yellow phosphorus: This is an intermediate form that is less stable than red and black phosphorus.

Conclusion:
Among these allotropes, black phosphorus is the most thermodynamically stable due to its low reactivity and stable structure, making option C the correct answer.