White crystalline solid (A) reacts with `H_2` to form a highly associated liquid (B) and a monoatomic , colourless gas (C ). The liquid (B) is used for etching glass. Compound (A) undergoes hydrolysis slowly to form (C ), (B) and a diatomic gas (D ) whose IE is almost similar to that of (C ). (B) forms an addition compound with KF to form (E) which is electrolysed in the molten state to form a most reactive gas (F) which combines with (C ) in 2:1 ratio of produce (A).
Which of the following is correct for the white crystalline solid (A) ?

Options

A. It oxidises `F^(-)` to `F_(2)`
B. It on hydrolysis with alkali under goes disproportionation.
C. It is obtained by the reaction of ( C) with `O_(2)F_(2)` at `118^(@)C`.
D. None of these

Answer

To solve the problem step by step, we will analyze the information given and deduce the identity of the white crystalline solid (A).

### Step 1: Identify the white crystalline solid (A)
- The question states that (A) is a white crystalline solid that reacts with hydrogen (H₂) to produce a highly associated liquid (B) and a monoatomic, colorless gas (C).
- The only white crystalline solid that fits this description is xenon difluoride (XeF₂).

**Hint:** Look for a white crystalline solid in the p-block elements that reacts with hydrogen.

### Step 2: Determine the products of the reaction
- When xenon difluoride (XeF₂) reacts with hydrogen, it forms xenon (C) and hydrofluoric acid (B), which is a highly associated liquid used for etching glass.
- Thus, we can identify:
- (B) = Hydrofluoric acid (HF)
- (C) = Xenon (Xe)

**Hint:** Consider the properties of the products formed from the reaction of (A) with hydrogen.

### Step 3: Analyze the hydrolysis of (A)
- The hydrolysis of xenon difluoride (XeF₂) produces xenon (C), hydrofluoric acid (B), and a diatomic gas (D).
- The diatomic gas (D) produced in this hydrolysis is likely to be fluorine (F₂), which has an ionization energy similar to that of xenon (C).

**Hint:** Hydrolysis often produces the original compound and may release a diatomic gas.

### Step 4: Identify the addition compound (E)
- The liquid (B), hydrofluoric acid (HF), forms an addition compound with potassium fluoride (KF) to produce (E), which is potassium hexafluoroxenate (K₂[XeF₆]).

**Hint:** Look for addition compounds that can form with hydrofluoric acid and a fluoride salt.

### Step 5: Electrolysis of (E)
- When (E) is electrolyzed in the molten state, it produces a highly reactive gas (F), which is fluorine (F₂).
- This fluorine gas (F) can react with xenon (C) in a 2:1 ratio to regenerate xenon difluoride (A).

**Hint:** Electrolysis often produces elemental gases, especially when dealing with halides.

### Conclusion
Based on the deductions made through the steps above, the white crystalline solid (A) is identified as xenon difluoride (XeF₂).

### Final Answer
The correct identification for the white crystalline solid (A) is **Xenon difluoride (XeF₂)**.