`A overset(Delta)rarrB` (oxide) `+ CO_(2)`
`B + H_(2)O rarr C`
`C+ CO_(2) rarrA` (milky)
`C+ NH_(4)CI overset(Delta)rarr D` (gas)
`D + H_(2)O + CO_(2) rarr E`
`E + NaCI rarr F`
`F overset(Delta)rarr Na_(2)CO_(3)+CO_(2)+H_(2)O`
Name of the process is:

Options

A. solvay
B. ammonia-soda
C. both correct
D. None is correct

Answer

To solve the question, we will analyze the series of reactions step by step and identify the process involved.

### Step-by-Step Solution:

1. **Identify the Initial Reaction**:
- The reaction starts with A (oxide) reacting with CO₂ to form B.
- Given that B is a product of A and CO₂, we can assume that A is calcium carbonate (CaCO₃), which decomposes upon heating to form calcium oxide (CaO) and carbon dioxide (CO₂).

2. **Formation of C**:
- The next reaction involves B (which we identified as CaO) reacting with H₂O to form C.
- Calcium oxide reacts with water to form calcium hydroxide (Ca(OH)₂), also known as slaked lime. Thus, C = Ca(OH)₂.

3. **Formation of A (Milky)**:
- C (calcium hydroxide) reacts with CO₂ to form A again.
- When calcium hydroxide reacts with carbon dioxide, it forms calcium carbonate, which is a milky white precipitate. Thus, A = CaCO₃.

4. **Formation of D (Gas)**:
- C (calcium hydroxide) reacts with NH₄Cl to produce D (gas).
- The reaction of calcium hydroxide with ammonium chloride produces calcium chloride, ammonia (NH₃), and water. Here, D = NH₃ (gas).

5. **Formation of E**:
- D (ammonia) reacts with H₂O and CO₂ to form E.
- Ammonia reacts with water and carbon dioxide to form ammonium carbonate (NH₄₂CO₃). Thus, E = NH₄CO₃.

6. **Formation of F**:
- E (ammonium carbonate) reacts with NaCl to form F.
- The reaction of ammonium carbonate with sodium chloride yields sodium bicarbonate (NaHCO₃) and ammonium chloride. Thus, F = NaHCO₃.

7. **Final Reaction**:
- F (sodium bicarbonate) is heated to produce Na₂CO₃.
- When sodium bicarbonate is heated, it decomposes to form sodium carbonate (Na₂CO₃), carbon dioxide (CO₂), and water (H₂O).

8. **Identify the Process**:
- The entire series of reactions describes the preparation of sodium carbonate from calcium carbonate and ammonium chloride through various intermediate steps.
- This process is known as the **Solvay process**.

### Final Answer:
The name of the process is: **Solvay process**.