Problem 212 - A Complete Resource Book in Chemistry for JEE Main

Question

Which one of the following reactions of Xenon compound is not feasible? (a) \(3 \mathrm{XeF}_{4}+6 \mathrm{H}_{2} \mathrm{O} \longrightarrow 2 \mathrm{Xe}+\mathrm{XeO}_{3}+12 \mathrm{HF}+1.5 \mathrm{O}_{2}\) (b) \(2 \mathrm{XeF}_{2}+2 \mathrm{H}_{2} \mathrm{O} \longrightarrow 2 \mathrm{Xe}+4 \mathrm{HF}+\mathrm{O}_{2}\) (c) \(\mathrm{XeF}_{6}+\mathrm{RbF} \longrightarrow \mathrm{Rb}\left[\mathrm{XeF}_{7}\right]\) (d) \(\mathrm{XeO}_{3}+6 \mathrm{HF} \longrightarrow \mathrm{XeF}_{6}+3 \mathrm{H}_{2} \mathrm{O}\)

Step-by-Step Solution

Answer

Reaction (d) is not feasible because it involves an unlikely oxidation.

Step 1: Analyzing Reaction Feasibility

To determine which reactions are feasible, we need to consider the stability and reactivity of the products and reactants. Reactions are generally feasible if they result in lower energy states, formation of stable products, or are thermodynamically favorable.

Step 2: Analyze Reaction (a)

In reaction (a), Xenon tetrafluoride (XeF_4) reacts with water. The products include Xenon gas, which is a stable noble gas, XeO_3,
2HF, and oxygen. This reaction is feasible as it results in the formation of Xe gas, which is highly stable.

Step 3: Analyze Reaction (b)

Reaction (b) involves Xenon difluoride (XeF_2) reacting with water to form Xe gas, HF, and oxygen. Xe gas is highly stable, making this reaction favorable and feasible.

Step 4: Analyze Reaction (c)

In reaction (c), XeF_6 reacts with RbF to form Rb[XeF_7]. This compound, Rb[XeF_7], is known in chemistry and reaction with rubidium fluoride is feasible.

Step 5: Analyze Reaction (d)

Reaction (d) consists of XeO_3 reacting with
6HF to form XeF_6 and H_2O. This reaction is not feasible as hydrofluoric acid (
6HF) is not likely to oxidize XeO_3 to XeF_6 and H_2O in normal conditions.

Step 6: Conclusion

Given the analysis, reaction (c) and reaction (d) involve formations of compounds that are stable and known. However, reaction (d) involves an improbable reaction scenario making it not feasible at standard conditions.

Key Concepts

Reaction Feasibility

To understand whether a chemical reaction will occur, it’s important to consider its feasibility. This involves analyzing several factors like energy requirements and stability of the resulting products. Reactions tend to be feasible if they lead to more stable products or if they are energetic enough to proceed without external energy input.

Several indicators can help predict the feasibility:

• Lower energy products: Reactions that result in products with less energy than the original reactants are often feasible.
• Stable products: Formation of stable substances, such as nobel gases or water, suggests feasibility.
• Thermodynamic favorability: A reaction that is thermodynamically favorable will likely happen under normal conditions.

By considering these aspects, we can identify if a given xenon reaction is feasible or not, like seeing if Xenon difluoride reacting with water to yield Xenon and HF is feasible due to production of stable xenon gas and HF.

Noble Gases

Noble gases, found in Group 18 of the periodic table, include elements such as helium, neon, and xenon. Known for their lack of reactivity, these elements are stable due to their full valence electron shells, which make them unlikely to engage in chemical reactions under normal conditions.

Considerations about noble gases:

• Inert nature: Because they have a full set of electrons, noble gases don’t need to gain or lose electrons to achieve stability.
• Limited bonding: They rarely form compounds because they are energetically satisfied and don't form strong bonds with other elements.

The stability that derives from their electronic configuration makes reactions involving noble gases unique, as seen in the feasibility of xenon compounds to form stable products like xenon gas.

Xenon Compounds

Xenon is one rare noble gas that can actually form compounds, despite the general inertness of noble gases. This happens because xenon can sometimes be coaxed into forming bonds under specific conditions, often involving high pressures or with certain reactive elements like fluorine.

Key points about xenon compounds:

• Reactivity with fluorine: Xenon forms stable compounds such as XeF₂, XeF₄, and XeF₆ by reacting with fluorine, one of the most reactive nonmetals.
• Applications: Xenon compounds are studied for their potential uses in various fields, including lighting and medical imaging.

Learning about the ability of xenon to form compounds helps understand reactions like XeF₆ forming exotically stable compounds as seen in the reaction involving RbF to form Rb[ XeF₇].

Stability of Molecules

In chemistry, molecular stability is a key factor determining how a compound behaves in reactions. A stable molecule usually requires significant energy to reconfigure its structure, decreasing its likelihood to react spontaneously.

Aspects influencing molecular stability:

• Bond strength: Stronger bonds within a molecule imply greater molecular stability.
• Electron configuration: Molecules with full valence shells are often more stable.
• Environmental conditions: Factors like temperature and pressure can impact stability.

Understanding stability is vital to predict if a xenon-related reaction is likely to occur. For instance, reactions leading to the formation of molecules like Xe, which are inherently stable, are often feasible, whereas reactions forming less stable intermediates may not proceed. Such reasoning explains why certain reactions involving xenon are feasible, while others, like converting XeO₃ with HF to form XeF₆, are not feasible under standard conditions.