In the synthesis of sodium carbonate, the recovery of ammonia is done by treating `NH_(4)Cl` with `Ca(OH)_(2)`. The by-product obtained in this process is

Options

A. `CaCl_(2)`
B. `NaCl`
C. `NaOH`
D. `NaHCO_(3)`

Explanation

To solve the question regarding the by-product obtained when treating \( NH_4Cl \) with \( Ca(OH)_2 \) in the recovery of ammonia during the synthesis of sodium carbonate, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**: The reactants in this process are ammonium chloride (\( NH_4Cl \)) and calcium hydroxide (\( Ca(OH)_2 \)).

2. **Write the Chemical Reaction**: When \( NH_4Cl \) reacts with \( Ca(OH)_2 \), the reaction can be represented as:
\[ 2 NH_4Cl + Ca(OH)_2 \rightarrow 2 NH_3 + CaCl_2 + 2 H_2O \]

3. **Analyze the Products**: From the balanced chemical equation, we can see that the products formed are:
- Ammonia (\( NH_3 \))
- Calcium chloride (\( CaCl_2 \))
- Water (\( H_2O \))

4. **Identify the By-Product**: The question specifically asks for the by-product of the reaction. In this case, the by-product is \( CaCl_2 \) (calcium chloride).

5. **Conclusion**: Therefore, the by-product obtained in the process of recovering ammonia from \( NH_4Cl \) using \( Ca(OH)_2 \) is \( CaCl_2 \).

### Final Answer:
The by-product obtained in this process is \( CaCl_2 \) (calcium chloride).

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