Problem 27 - Chemistry in 30 days

Question

Which of the following series of xenon fluorides is known? (a) \(\mathrm{XeF}_{2}, \mathrm{XeF}_{4}, \mathrm{XeF}_{3}\) (b) \(\mathrm{XeF}_{2}, \mathrm{XeF}_{4}, \mathrm{XeF}_{6}\) (c) \(\mathrm{XeF}_{2}, \mathrm{XeF}_{3}, \mathrm{XeF}_{6}\) (d) \(\mathrm{XeF}_{2}, \mathrm{XeF}_{4}, \mathrm{XeF}_{5}\)

Step-by-Step Solution

Answer

The correct answer is (b).

Step 1: Review Known Xenon Fluorides

Xenon fluorides are compounds of xenon and fluorine. The known xenon fluorides are \(\mathrm{XeF}_2\), \(\mathrm{XeF}_4\), and \(\mathrm{XeF}_6\). These are the xenon fluorides that have been successfully and stably synthesized and characterized.

Step 2: Evaluate Option (a)

Option (a) lists \(\mathrm{XeF}_2\), \(\mathrm{XeF}_4\), and \(\mathrm{XeF}_3\). \(\mathrm{XeF}_3\) is not a known stable xenon fluoride compound, so this option is incorrect.

Step 3: Evaluate Option (b)

Option (b) lists \(\mathrm{XeF}_2\), \(\mathrm{XeF}_4\), and \(\mathrm{XeF}_6\). All these compounds \(\mathrm{XeF}_2\), \(\mathrm{XeF}_4\), and \(\mathrm{XeF}_6\) are known stable compounds, making this option correct.

Step 4: Evaluate Option (c)

Option (c) lists \(\mathrm{XeF}_2\), \(\mathrm{XeF}_3\), and \(\mathrm{XeF}_6\). \(\mathrm{XeF}_3\) is not a known stable xenon fluoride compound, so this option is incorrect.

Step 5: Evaluate Option (d)

Option (d) lists \(\mathrm{XeF}_2\), \(\mathrm{XeF}_4\), and \(\mathrm{XeF}_5\). There is no stable known compound \(\mathrm{XeF}_5\), so this option is incorrect.

Key Concepts

Xenon Compounds

Xenon compounds, especially its fluorides, mark an important chapter in the world of chemistry. Xenon is a noble gas, which are traditionally known for their lack of reactivity due to their full valence electron shells. This very nature of xenon makes its reactions with other elements fascinating. This inertness was long believed to render xenon incapable of forming compounds. However, in the 1960s, scientists discovered it could form stable chemical bonds, notably with fluorine, due to the high electronegativity and small size of fluorine. Xenon fluorides such as \( \mathrm{XeF}_2 \), \( \mathrm{XeF}_4 \), and \( \mathrm{XeF}_6 \) are notable examples of xenon forming such stable compounds.

Stable Compounds

Stability in chemical compounds refers to the compound’s ability to maintain its form under normal conditions. Xenon fluorides are notable because they are stable under specific laboratory conditions yet remain reactive enough to partake in further chemical reactions under controlled situations.

• \( \mathrm{XeF}_2 \) is a linear molecule that remains stable at room temperature and has found applications in fields ranging from advanced materials to chemical synthesis.
• \( \mathrm{XeF}_4 \) is a square planar molecule that also maintains stability under normal conditions, showing that xenon can indeed hold multiple fluorine atoms stably.
• \( \mathrm{XeF}_6 \), despite containing six fluorine atoms, remains stable and exhibits interesting chemical behavior such as hydrolysis in water.

Understanding the stability of these xenon compounds is crucial for harnessing their potential in both elemental and applied chemistry.

Chemical Characterization

Chemical characterization involves understanding the structure, properties, and reactivity of compounds. For xenon fluorides, understanding these factors is important for their practical applications.

Molecular Geometry and Hybridization

• \( \mathrm{XeF}_2 \) features a linear geometry due to sp³d hybridization, aligning its bonds symmetrically.
• \( \mathrm{XeF}_4 \) adopts a square planar shape, facilitated by dsp³d hybridization, making it symmetrical and therefore stable.
• \( \mathrm{XeF}_6 \) holds an octahedral geometry, supported by sp³d² hybridization, allowing it to conjugate six fluorine atoms.

Reactivity and Application

Xenon fluorides have distinct reactivity profiles:

• They are capable of acting as fluorinating agents, where they introduce fluorine into other molecules.
• They serve uses in synthesis and research, particularly within inorganic chemistry.

Characterizing xenon fluorides chemically enables deeper engagement with noble gas chemistry, challenging the traditional views on the chemical inertness of xenon.