Question

Which of the following are correct statements about white phosphorus $\left( {{P_4}} \right)$?
A. Each $P$ atom has one lone pair of electrons in a molecule of ${P_4}$.
B. It has tetrahedral structure with ${109^o}28'$ bond angle.
C. There are six $P - P$ linkages in a molecule of ${P_4}$.
D. It undergoes disproportionation on reaction with alkalis.

Answer 1

The white phosphorus has a similar structure as that of a pyramid and hence the characters are similar. Therefore the factors related to the number of electrons involved in the reaction which helps in determining the products formed at the end of the reaction.

Complete step by step answer:
There are five valence electrons according to the electronic configuration of every $P$ atom. Among those electrons, three electrons are responsible for bond formation with the other three $P$ atoms in the ${P_4}$ molecule. There are two residual electrons in each atom which is present as a lone pair for each of the atoms. These associations are responsible for bond formation in the molecule and as a result, the pyramidal structure of ${P_4}$ is formed. The pyramidal structure has all the four atoms associated at a specific bond angle.
All the structures in the pyramid are equilateral triangles and that is why the bond angle is ${60^o}$ for all the bonds in the ${P_4}$ residue. There are a total six edges in a pyramidal structure and similarly, there are six $P - P$ linkages in the main structure of ${P_4}$ molecule. These linkages form the stable structure of white phosphorus and the bond angle remains stable in its configuration as well.
The ${P_4}$ molecule can undergo disproportionation reaction in the presence of a specific alkali. The disproportionation reaction takes place in the presence of $NaOH$ where it forms $P{H_3}$ or phosphine.
${P_4} + 3NaOH + 3{H_2}O \to 3Na{H_2}P{O_2} + P{H_3}$

Therefore, the options A, C and D are true about white phosphorus ${P_4}$ but the statement B is not true as both the structure and bond angles are different for the molecule.

Note:
Stability of the structure depends on the bond angle or the atoms involved in the formation of the molecule. The white phosphorus can react fast in the presence of strong alkali.