The main process for the manufacture of sodium carbonate is

Options

A. Carbon process
B. Solvay process
C. Down's process
D. Nelson process

Answer

**Step-by-Step Solution:**

1. **Identify the Process**: The main process for the manufacture of sodium carbonate (Na2CO3) is known as the Solvay process, also referred to as the Solvay ammonia process.

2. **Starting Material**: The process begins with calcium carbonate (CaCO3) as the primary raw material.

3. **Decomposition of Calcium Carbonate**: Calcium carbonate is heated to produce calcium oxide (CaO) and carbon dioxide (CO2). The reaction can be represented as:
\[ \text{CaCO}_3 \rightarrow \text{CaO} + \text{CO}_2 \]

4. **Formation of Calcium Hydroxide**: The calcium oxide (CaO) then reacts with water (H2O) to form calcium hydroxide (Ca(OH)2):
\[ \text{CaO} + \text{H}_2\text{O} \rightarrow \text{Ca(OH)}_2 \]

5. **Reaction with Ammonium Chloride**: Calcium hydroxide reacts with ammonium chloride (NH4Cl) to produce ammonia (NH3) and ammonium carbonate:
\[ \text{Ca(OH)}_2 + \text{NH}_4\text{Cl} \rightarrow \text{NH}_3 + \text{CaCl}_2 + \text{H}_2\text{O} \]

6. **Formation of Sodium Bicarbonate**: Ammonia (NH3) then reacts with sodium chloride (NaCl) in the presence of carbon dioxide (CO2) and water to produce sodium bicarbonate (NaHCO3):
\[ \text{NH}_3 + \text{NaCl} + \text{CO}_2 + \text{H}_2\text{O} \rightarrow \text{NaHCO}_3 + \text{NH}_4\text{Cl} \]

7. **Conversion to Sodium Carbonate**: Sodium bicarbonate (NaHCO3) is then heated to produce sodium carbonate (Na2CO3):
\[ 2\text{NaHCO}_3 \rightarrow \text{Na}_2\text{CO}_3 + \text{CO}_2 + \text{H}_2\text{O} \]

8. **Cycle Continuation**: The process is cyclic, as the ammonium chloride (NH4Cl) produced can be recycled back into the process.

9. **Conclusion**: The overall process results in the production of sodium carbonate (Na2CO3) from calcium carbonate (CaCO3) through a series of reactions involving ammonia and sodium chloride.

**Final Answer**: The main process for the manufacture of sodium carbonate is the Solvay process.

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