Problem 157 - A Complete Resource Book in Chemistry for JEE Main

Question

Number of P-O bonds in \(\mathrm{P}_{4} \mathrm{O}_{10}\) is (a) 17 (b) 16 (c) 15 (d) 6

Step-by-Step Solution

Answer

The number of P-O bonds in \( \text{P}_{4}\text{O}_{10} \) is 16.

Step 1: Understanding the problem

We need to determine the number of P-O bonds in the molecule \( \text{P}_{4}\text{O}_{10} \). This requires knowledge of both its chemical structure and bonding.

Step 2: Sketch the molecular structure

The compound \( \text{P}_{4}\text{O}_{10} \) is formed by four phosphorus atoms and ten oxygen atoms. This compound can be described as having interconnected \( \text{P-O} \) bonds forming a complex structure. Thus, drawing its structure is helpful in determining the number of such bonds.

Step 3: Identify the type of bonds

The structure of \( \text{P}_{4}\text{O}_{10} \) can be visualized from its standard depiction: it consists of a network of four \( \text{P-O-P} \) bridges and around each of the \( \text{P} \) atoms, there are additional \( \text{P=O} \) double bonds.

Step 4: Counting phosphorus-oxygen bonds

In the molecule, each phosphorus (P) is bonded to four oxygen atoms which include one double-bond (\( \text{P=O} \)) and three single bonds (\( \text{P-O} \)). With four phosphorus atoms each bonded to four oxygen atoms, we initially count 4 \( \times \) 4 = 16 single bonds. However, we also need to consider double bonds which account for P=O bonds.

Step 5: Adjusting for counting overlap

Each \( \text{P=O} \) is counted as a single entity supplied by a single P atom, and overlaps with the P singly linked to another O in certain configurations. Thus the complete single bond count sums up to 16 distinct \( \text{P-O} \) single bonds in actual configuration, when effectively accounting for double bonds.

Key Concepts

Phosphorus-Oxygen Bonds

In the molecule \(\text{P}_{4}\text{O}_{10}\), phosphorus and oxygen atoms are connected by both single and double bonds. Each phosphorus atom forms bonds with four oxygen atoms, but the nature of these bonds varies. There are two types of phosphorus-oxygen bonds present in this molecule:

• Single bonds (\(\text{P-O}\))
• Double bonds (\(\text{P=O}\))

Each phosphorus atom has one double bond with an oxygen atom and forms three single bonds with three other oxygen atoms. By imagining this structure, we can better understand how the atoms are arranged and how the bonds are distributed. Analyzing such molecular structures often helps chemists infer the properties and reactivity of the compounds.

Chemical Bonding

Chemical bonding in \(\text{P}_{4}\text{O}_{10}\) features an intricate network that involves different types of interactions between phosphorus and oxygen atoms. These bonds are the cornerstone of chemical structures as they hold atoms together.
In \(\text{P}_{4}\text{O}_{10}\), each phosphorus begins by making a double bond called \(\text{P=O}\), where both atoms share two electron pairs.

This is considered a stronger bond compared to a single bond. Then, each phosphorus atom forms additional three single bonds, \(\text{P-O}\), using just one electron pair each.
This combination of bonding types provides the molecule with stability and a specific three-dimensional shape, which impacts its chemical properties.

Molecular Geometry

The molecular geometry of \(\text{P}_{4}\text{O}_{10}\) plays an important role in defining both its function and stability. Understanding the overall shape helps in grasping molecular behavior and interaction patterns.
The molecule consists of four phosphorus atoms linked together via oxygen bridges, often described as forming a tetrahedral arrangement. Each phosphorus atom is at the center of a smaller tetrahedron.

These arrangements lead to a relatively complex structure, often pictured as two tetrahedra sharing a common edge. This geometry is not only interesting but also significant in determining the ability of \(\text{P}_{4}\text{O}_{10}\) to interact with other molecules or ions. Being able to visualize this shape greatly aids in learning complex chemical concepts and mastering topics related to chemical bonding and molecular structures.