Question

Correct statement(s) about the compounds P, Q and R is(are)
\( \text{Xe(g)} + \text{F}_2\text{(g)} \xrightarrow{\text{873 K, 7 bar}}{\text{P}} \)
(1 : 5 ratio)
\( \text{P} + \text{O}_2\text{F}_2 \xrightarrow{\text{143 K}}{\text{Q}} + \text{O}_2 \)
\( \text{Q} + \text{H}_2\text{O} \xrightarrow{\text{complete hydrolysis}}{\text{R}} + \text{HF} \)

• A. P has two lone pairs of electrons on the central atom.
• B. Q has a perfect octahedral geometry.
• C. Q can act as a fluorinating agent.
• D. The molecular structure of R is trigonal pyramidal.

Hint:

For xenon compounds:
- XeF$_2$: Linear, 3 lone pairs.
- XeF$_4$: Square planar, 2 lone pairs.
- XeF$_6$: Distorted octahedral, 1 lone pair.
- XeO$_3$: Trigonal pyramidal, 1 lone pair.
- XeOF$_4$: Square pyramidal, 1 lone pair.
Remember that XeF$_2$, XeF$_4$, XeF$_6$ are strong fluorinating agents. Also, hydrolysis of higher xenon fluorides leads to xenon oxyfluorides or xenon oxides.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question presents a three-step reaction sequence involving xenon, fluorine, and other reagents to form compounds P, Q, and R. We need to identify the correct statements about these compounds. This question might have multiple correct answers.
Step 2: Key Formula or Approach:
1. Identify compounds P, Q, and R by analyzing each reaction step.
2. Determine the properties, geometry, and hybridization for each compound using VSEPR theory and knowledge of chemical reactions.
Step 3: Detailed Explanation:
Let's identify P, Q, and R:
Reaction 1: \( \text{Xe(g) + \text{F}_2\text{(g)} \xrightarrow{\text{873 K, 7 bar}}{\text{P}} \)}
Xenon reacts with fluorine under specific conditions to form xenon fluorides. The ratio 1:5 of Xe:F$_2$ is important. Higher ratios of F$_2$ tend to form higher fluorides.
Given the conditions (high temperature, 1:5 ratio), this reaction yields XeF$_4$ (xenon tetrafluoride) or XeF$_6$ (xenon hexafluoride). XeF$_6$ is formed at higher fluorine ratios (1:20) and higher temperatures/pressures. At 1:5, it is usually XeF$_4$. Let's assume P = XeF$_4$ first.
Reaction 2: \( \text{P} + \text{O}_2\text{F}_2 \xrightarrow{\text{143 K}}{\text{Q}} + \text{O}_2 \)
This is a known reaction used for the synthesis of XeF$_6$. $O_2F_2$ is a powerful fluorinating agent.
If P = XeF$_4$, then $XeF_4 + O_2F_2 \xrightarrow{143 K} XeF_6 + O_2$. So, Q = XeF$_6$.
Reaction 3: \( \text{Q} + \text{H}_2\text{O} \xrightarrow{\text{complete hydrolysis}}{\text{R}} + \text{HF} \)
Xenon hexafluoride (XeF$_6$) undergoes complete hydrolysis with water. Complete hydrolysis of XeF$_6$ yields xenon trioxide ($XeO_3$) and hydrofluoric acid (HF).
$XeF_6 + 3H_2O \rightarrow XeO_3 + 6HF$. So, R = XeO$_3$.
Now let's evaluate the statements based on P=XeF$_4$, Q=XeF$_6$, R=XeO$_3$:
(A) P has two lone pairs of electrons on the central atom.
P = XeF$_4$. Central atom is Xe.
Valence electrons of Xe = 8.
Xe forms 4 single bonds with F. So, 4 bonding pairs.
Remaining electrons = $8 - 4 = 4$. So, 2 lone pairs.
Steric number = $4 + 2 = 6$. Electron geometry: Octahedral. Molecular geometry: Square planar.
This statement is Correct.
(B) Q has a perfect octahedral geometry.
Q = XeF$_6$. Central atom is Xe.
Valence electrons of Xe = 8.
Xe forms 6 single bonds with F. So, 6 bonding pairs.
Remaining electrons = $8 - 6 = 2$. So, 1 lone pair.
Steric number = $6 + 1 = 7$. Electron geometry: Pentagonal bipyramidal.
Molecular geometry: Distorted octahedral (due to the presence of one lone pair). It is not a perfect octahedral geometry.
This statement is Incorrect.
(C) Q can act as a fluorinating agent.
Q = XeF$_6$. Xenon hexafluoride is a very powerful fluorinating agent. It can react with other compounds to transfer fluorine atoms, often oxidizing the other compound. For example, $XeF_6 + H_2O \rightarrow XeOF_4 + 2HF$. It can also react with silica to form $XeOF_4$.
This statement is Correct.
(D) The molecular structure of R is trigonal pyramidal.
R = XeO$_3$. Central atom is Xe.
Valence electrons of Xe = 8.
Xe forms 3 double bonds with O. So, 3 sigma bonds. (Xe also has one lone pair).
Remaining electrons = $8 - (3 \times 2) = 2$. So, 1 lone pair.
Steric number = $3 + 1 = 4$. Electron geometry: Tetrahedral.
Molecular geometry: Trigonal pyramidal (due to the presence of one lone pair).
This statement is Correct.
We have found three correct statements (A, C, D). The question allows for multiple correct answers.
Step 4: Final Answer:
Statements (A), (C), and (D) are correct.