Number of molecules having p-d bonding

To determine the number of molecules among the given options that have p-d bonding, we need to understand the concept of p-d bonding and analyze the chemical structures of each compound.

P4O10:
P4O10 is an oxide of phosphorus. It consists of four phosphorus atoms and ten oxygen atoms. The structure of P4O10 can be represented as follows:

O
||
O-P-O-P-O-P-O-P-O
||
O

In P4O10, each phosphorus atom forms five sigma bonds, resulting in a total of 20 sigma bonds. The bonding in P4O10 is primarily covalent, and there are no p-d bonds present. Therefore, P4O10 does not have p-d bonding.

N2O5:
N2O5 is an oxide of nitrogen. It consists of two nitrogen atoms and five oxygen atoms. The structure of N2O5 can be represented as follows:

O
||
O-N-O-N-O-O
||
O

In N2O5, each nitrogen atom forms three sigma bonds and one pi bond, resulting in a total of eight sigma bonds and two pi bonds. The pi bond between the nitrogen and oxygen atoms is an example of p-d bonding. Therefore, N2O5 has one p-d bond.

(SiH3)3N:
(SiH3)3N is a compound that contains silicon, hydrogen, and nitrogen. The structure of (SiH3)3N can be represented as follows:

H H H
| | |
H-Si-Si-Si-N
| | |
H H H

In (SiH3)3N, each silicon atom forms four sigma bonds, resulting in a total of 12 sigma bonds. The bonding between the silicon and nitrogen atoms involves the overlap of p and d orbitals, resulting in p-d bonding. Therefore, (SiH3)3N has three p-d bonds.

SO3:
SO3 is an oxide of sulfur. It consists of one sulfur atom and three oxygen atoms. The structure of SO3 can be represented as follows:

O
||
O=S=O
||
O

In SO3, each sulfur atom forms two sigma bonds and one pi bond, resulting in a total of six sigma bonds and two pi bonds. The pi bond between the sulfur and oxygen atoms is an example of p-d bonding. Therefore, SO3 has one p-d bond.

Summary:
- P4O10 does not have p-d bonding.
- N2O5 has one p-d bond.
- (SiH3)3N has three p-d bonds.
- SO3 has one p-d bond.

Therefore, among the given options, the correct answer is '3' as (SiH3)3N, N2O5, and SO3 have p-d bonding.