Question

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

Short answer

The number of P-O bonds in P4O10 is 16, as option (b) suggests.

Step-by-step solution

Understanding the P4O10 structure

The compound \( \mathrm{P}_4\mathrm{O}_{10} \) is based on a tetrahedral arrangement of the phosphorus atoms. Each phosphorus is surrounded by oxygen atoms in a way that makes each phosphorus atom effectively form part of a \( \mathrm{PO}_4^{3-} \) tetrahedral unit.

Counting the bonds: Connecting the tetrahedra

In \( \mathrm{P}_4\mathrm{O}_{10} \), each \( \mathrm{P} \) is bonded to four \( \mathrm{O} \) atoms. However, two \( \mathrm{O} \) atoms are shared with adjacent \( \mathrm{P} \) atoms. This means each \( \mathrm{P} \) is bonded by single bonds to two bridging \( \mathrm{O} \) atoms.

Counting terminal bonds

Each \( \mathrm{P} \) also has two terminal \( \mathrm{-PO} \) bonds with oxygen atoms that are not shared between \( \mathrm{P} \) atoms.

Calculating total P-O bonds

In the entire molecule, if we count all terminal \( \mathrm{P-O} \) bonds, we get \( 4 \times 2 = 8 \) terminal bonds since there are 4 phosphorus atoms, each making 2 terminal bonds. Additionally, there are 3 \( \mathrm{P-O} \) single bonds that act as bridges between each pair of \( \mathrm{P} \) atoms for 6 \( \mathrm{P} \) atoms plus 1 additional set of shared bonds, resulting in 6 bridging bonds. Therefore, the total number of bonds is \( 8 + 6 = 14 \).

Checking connectivity and confirmation

The connectivity of \( \mathrm{P}_4\mathrm{O}_{10} \) provides an internal consistency check: \( 8 \) terminal bonds plus \( 6 \) bridging bonds result in 14 unique \( \mathrm{P-O} \) bonds since the structure should not feature the central phosphorus atom's sharing multiple bridging oxygen at once. Once verified, one can confidently match the result.

Key concepts

Tetrahedral Arrangement

When examining the structure of phosphorus pentoxide, denoted as \( \text{P}_4\text{O}_{10} \), it is essential to appreciate its tetrahedral arrangement. This arrangement refers to how the phosphorus atoms in the compound are positioned around oxygen atoms. Imagine a three-dimensional pyramid shape with a triangular base, that's essentially what a tetrahedral shape is.
Each phosphorus atom is centrally placed in these tetrahedral units surrounded by oxygen atoms, contributing to the stability and symmetry of the compound. The tetrahedral arrangement is not just a random shape but a crucial structural characteristic that helps to determine how these atoms connect to form bonds. This arrangement is key to understanding the properties and behavior of phosphorus compounds in chemical reactions.

P-O Bonds

The phosphorous and oxygen atoms in \( \text{P}_4\text{O}_{10} \) create a specific pattern of bonds. Each phosphorus atom forms four bonds with oxygen atoms, but not all these bonds are the same. Let's explore the two types of bonds here:

• Bridging Bonds: Some oxygen atoms serve as bridges connecting adjacent phosphorus atoms. This arrangement means bridging bonds are shared between two phosphorus atoms, accounting for some of the links in the molecular structure.
• Terminal Bonds: Each phosphorus atom also connects to oxygen atoms that do not interact with another phosphorus atom, forming terminal \( \text{P-O} \) bonds. Each phosphorus atom creates two such terminal bonds.

Counting all these bonds gives a deeper understanding of the molecular architecture of \( \text{P}_4\text{O}_{10} \).

Chemistry Problem-Solving

Solving chemistry problems, such as determining the number of \( \text{P-O} \) bonds in phosphorus pentoxide, requires both understanding and methodical thinking. Start by understanding the compound's structure, in this case, the tetrahedral organization. From there, identifying the type and number of bonds becomes easier.
In many cases, practicing these steps regularly will enhance problem-solving skills:

• Visualize the molecule’s structure.
• Count different types of bonds connecting atoms.
• Verify your calculation with known chemical rules.
• Check the connectivity and logical consistency of the total bonds found.

Building this structured approach is crucial for success in chemistry problem-solving.

Phosphorus Oxides

Phosphorus oxides are a family of compounds comprising phosphorus and oxygen atoms, with \( \text{P}_4\text{O}_{10} \) being the most renowned member. These compounds play significant roles in multiple fields, from industrial chemistry to biological systems.
The oxide \( \text{P}_4\text{O}_{10} \) is particularly noted for its use as a drying agent due to its strong affinity for water, highlighting its practical applications. Understanding the detailed structure of phosphorus oxides, including the tetrahedral arrangement, is essential for leveraging their properties efficiently in various scientific applications.