Problem 139 - A Complete Resource Book in Chemistry for JEE Main

Question

Pick out the correct statements for \(\mathrm{XeF}_{6^{*}}\) (1) it reacts with \(\mathrm{SiO}_{2}\) to form \(\mathrm{XeOF}_{4}\) (2) \(\mathrm{XeF}_{6}\) is hydrolyzed partially to form \(\mathrm{XeOF}_{4}\) (3) it acts as \(\mathrm{F}^{-}\)acceptor when treated with alkali metal fluoride, but cannot act as \(\mathrm{F}^{-}\)donor to form complexes. (4) On complete hydrolysis, it forms \(\mathrm{XeO}_{3}\) (a) 1,3 and 4 (b) 1,2 and 4 (c) 2,3 and 4 (d) 2 and 4 only

Step-by-Step Solution

Answer

The correct statements for \( \mathrm{XeF}_6 \) are (1), (2), and (4). Option (b) 1, 2 and 4 is correct.

Step 1: Analyzing the Reactivity with SiO2

First, check if the reaction of \( \mathrm{XeF}_6 \) with \( \mathrm{SiO}_2 \) to form \( \mathrm{XeOF}_4 \) is a valid statement. Xenon hexafluoride reacts with silica, \( \mathrm{SiO}_2 \), producing \( \mathrm{XeOF}_4 \) and \( \mathrm{SiF}_4 \). Hence, statement (1) is correct.

Step 2: Partial Hydrolysis of XeF6

Next, consider the partial hydrolysis of \( \mathrm{XeF}_6 \). When \( \mathrm{XeF}_6 \) undergoes hydrolysis, it forms \( \mathrm{XeOF}_4 \) among other products. Thus, statement (2) is correct.

Step 3: Evaluating F- Acceptor and Donor Ability

The statement about \( \mathrm{XeF}_6 \) acting as \( \mathrm{F}^{-} \) acceptor is true, as it forms complexes like \( \mathrm{XeF}_7^- \) with fluoride ions. However, \( \mathrm{XeF}_6 \) can also act as an \( \mathrm{F}^{-} \) donor under some conditions. Therefore, statement (3) is not completely correct as it incorrectly claims that it cannot act as an \( \mathrm{F}^{-} \) donor.

Step 4: Complete Hydrolysis of XeF6

On complete hydrolysis, \( \mathrm{XeF}_6 \) transforms into \( \mathrm{XeO}_3 \). This means statement (4) is correct.

Step 5: Conclusion from Analysis

From the analysis, statements 1, 2, and 4 are correct. Therefore, the correct option is (b) 1, 2 and 4.

Key Concepts

XeF6 reactivity with SiO2

Xenon hexafluoride, commonly known as XeF6, is a fascinating compound due to its unusual reactivity. It reacts with silica, which is represented chemically as \( \mathrm{SiO}_2 \). This reaction is quite intriguing for chemistry students as it results in the formation of xenon oxyfluoride \( \mathrm{XeOF}_4 \) and silicon tetrafluoride \( \mathrm{SiF}_4 \).
This characteristic reaction can be explained by considering the strong oxidizing properties of XeF6, which facilitates the cleavage of the Si-O bond through a substitution mechanism. In this reaction, XeF6 essentially serves as a fluorinating agent, a property that is particularly useful in synthetic chemistry.
The balanced chemical equation for this transformation is:
\[ \mathrm{XeF}_6 + \mathrm{SiO}_2 \rightarrow \mathrm{XeOF}_4 + \mathrm{SiF}_4 \]
This reaction showcases the ability of XeF6 to engage in significant reactions with other compounds, modifying them and forming new compounds with distinct properties.

Partial hydrolysis of XeF6

Partial hydrolysis of xenon hexafluoride (XeF6) is an important process in understanding its chemical behavior. During partial hydrolysis, water interacts with XeF6 causing partial substitution of fluorine atoms with hydroxyl groups.
This incomplete hydrolysis results in the formation of xenon oxyfluoride \( \mathrm{XeOF}_4 \) along with other products. The process highlights the reactive nature of the Xe-F bonds, which, under controlled conditions, can be partially replaced by oxygen.
The chemical equation representing this partial hydrolysis is:
\[ \mathrm{XeF}_6 + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{XeOF}_4 + 2 \mathrm{HF} \]
Here you can see how simply adding water can alter the chemical structure of xenon hexafluoride, creating new bonds. This reaction is instrumental in illustrating the amphoteric behavior of XeF6, providing valuable insight for students into its potential use and manipulation in chemical reactions.

F- acceptor and donor properties of XeF6

Xenon hexafluoride (XeF6) has intriguing fluorine acceptor and donor characteristics. As a fluoride acceptor, XeF6 can accept an additional fluoride ion to form complex ions, such as \( \mathrm{XeF}_7^- \).
This ability is essential in extending the chemistry of XeF6, allowing it to participate in a wider range of chemical reactions. However, contrary to some misconceptions, XeF6 can also act as an \( \mathrm{F}^- \) donor under certain conditions.
This dual behavior means that XeF6 can exchange fluoride ions with other chemical species, acting effectively as a bridge in fluoride transfer reactions. This property is pivotal in understanding the versatility and adaptability of XeF6 in synthetic chemistry.
Such nuances make XeF6 a valuable compound, offering a variety of applications due to its flexible spectral properties and reactivity in different chemical environments.

Complete hydrolysis of XeF6

In the complete hydrolysis of xenon hexafluoride (XeF6), the compound undergoes a complete transformation reacting with water to yield different products. This reaction is more intense than partial hydrolysis and results in the formation of xenon trioxide \( \mathrm{XeO}_3 \).
The complete hydrolysis can be represented by the following chemical equation:
\[ \mathrm{XeF}_6 + 3\mathrm{H}_2\mathrm{O} \rightarrow \mathrm{XeO}_3 + 6\mathrm{HF} \]
This process highlights the full substitution of fluoride ions with hydroxyl ions. As a result, six molecules of hydrogen fluoride (HF) are produced.
Understanding the complete hydrolysis of XeF6 is important, as it demonstrates the full conversion from a fluoride complex to an oxide, which is essential in diverse fields, from theoretical chemistry to practical applications in catalysis and material science.