In the manufacture of sodium carbonate, following reactions are involved:
`(A) overset(Delta)rarr (B) + CO_(2)`
`(B) +H_(2)O rarr (C ) overset(+NH_(4)Cl rarr (D)overset(+H_(2)O)rarr underset("Solution")(E )`
`(E )+CO_(2)rarr (F)`
`(F)+NaCl rarr (G) overset("Heat")rarr Na_(2)CO_(3)+CO_(2)+H_(2)O`
(D) is a gas which is soluble in `H_(2)O`
(C ) is

Options

A. Calcium hydroxide
B. Sodium hydroxide
C. Calcium oxide
D. None of these

Explanation

To solve the question regarding the manufacture of sodium carbonate and identify the compound C, we will analyze the given reactions step by step.

### Step-by-Step Solution:

1. **Identify Compound A**:
- The process of manufacturing sodium carbonate involves starting with calcium carbonate (CaCO3).
- Therefore, **A = CaCO3**.

2. **Reaction of A**:
- When calcium carbonate is heated, it decomposes into calcium oxide (CaO) and carbon dioxide (CO2).
- This can be represented as:
\[ \text{CaCO}_3 \overset{\Delta}{\rightarrow} \text{CaO} + \text{CO}_2 \]
- Thus, **B = CaO**.

3. **Reaction of B with Water**:
- Calcium oxide reacts with water to form calcium hydroxide (Ca(OH)2).
- This can be represented as:
\[ \text{CaO} + \text{H}_2\text{O} \rightarrow \text{Ca(OH)}_2 \]
- Therefore, **C = Ca(OH)2**.

4. **Reaction of C with Ammonium Chloride (NH4Cl)**:
- Calcium hydroxide reacts with ammonium chloride to produce ammonia (NH3) and calcium chloride (CaCl2).
- This can be represented as:
\[ \text{Ca(OH)}_2 + 2\text{NH}_4\text{Cl} \rightarrow 2\text{NH}_3 + \text{CaCl}_2 + 2\text{H}_2\text{O} \]
- Here, **D = NH3** (ammonia), which is a gas that is soluble in water.

5. **Formation of E**:
- Ammonia (D) reacts with water to form ammonium hydroxide (NH4OH).
- This can be represented as:
\[ \text{NH}_3 + \text{H}_2\text{O} \rightarrow \text{NH}_4\text{OH} \]
- Therefore, **E = NH4OH**.

6. **Reaction of E with Carbon Dioxide**:
- Ammonium hydroxide reacts with carbon dioxide to form ammonium bicarbonate (NH4HCO3).
- This can be represented as:
\[ \text{NH}_4\text{OH} + \text{CO}_2 \rightarrow \text{NH}_4\text{HCO}_3 \]
- Thus, **F = NH4HCO3**.

7. **Reaction of F with Sodium Chloride (NaCl)**:
- Ammonium bicarbonate reacts with sodium chloride to produce sodium bicarbonate (NaHCO3) and ammonium chloride.
- This can be represented as:
\[ \text{NH}_4\text{HCO}_3 + \text{NaCl} \rightarrow \text{NaHCO}_3 + \text{NH}_4\text{Cl} \]
- Here, **G = NaHCO3**.

8. **Final Reaction**:
- Upon heating sodium bicarbonate, it decomposes to form sodium carbonate, carbon dioxide, and water.
- This can be represented as:
\[ \text{NaHCO}_3 \overset{\text{Heat}}{\rightarrow} \text{Na}_2\text{CO}_3 + \text{CO}_2 + \text{H}_2\text{O} \]

### Conclusion:
- The compound C is **Calcium Hydroxide (Ca(OH)2)**.