When sodium carbonate is added in excess to a metal chloride solution followed by the bromine water and then mixture is slightly heated , the solution turns apple green. The metal chloride is `:`

Options

A. `NiCl_(2)`
B. `CoCl_(2)`
C. `CrCl_(2)`
D. `FeCl_(3)`

Explanation

To solve the problem, we need to analyze the reactions that occur when sodium carbonate is added to a metal chloride solution, followed by bromine water, and then heating the mixture. The final solution turns apple green, which indicates the presence of a specific metal ion.

### Step-by-Step Solution:

1. **Identify the Metal Chloride**:
The metal chloride solution contains a metal ion (M) and chloride ions (Cl). We need to determine which metal chloride will react with sodium carbonate to produce a colored solution.

2. **Reaction with Sodium Carbonate**:
When sodium carbonate (Na2CO3) is added to the metal chloride (MCl2), a double displacement reaction occurs:
\[ MCl_2 + Na_2CO_3 \rightarrow MCO_3 + 2NaCl \]
This reaction produces a metal carbonate (MCO3) and sodium chloride (NaCl).

3. **Formation of Metal Carbonate**:
The metal carbonate (MCO3) can further react with excess sodium carbonate:
\[ MCO_3 + Na_2CO_3 \rightarrow MCO_3 \cdot Na_2CO_3 \]
This indicates that the metal carbonate is formed in a stable complex.

4. **Addition of Bromine Water**:
Next, bromine water (Br2) is added. The bromine reacts with water to form nascent oxygen:
\[ Br_2 + H_2O \rightarrow 2HBr + O \]
The nascent oxygen produced can oxidize certain metal ions.

5. **Formation of Apple Green Color**:
The nascent oxygen reacts with the metal carbonate complex to form a different metal carbonate that exhibits an apple green color. The specific metal that produces this color when oxidized is cobalt (Co):
\[ CoCO_3 + O \rightarrow Co^{3+} + CO_2 + H_2O \]
The presence of Co^{3+} ions gives the solution an apple green color.

6. **Conclusion**:
Based on the above reactions and the color change observed, the metal chloride in the solution is cobalt(II) chloride (CoCl2).

### Final Answer:
The metal chloride is **CoCl2** (Cobalt(II) chloride).

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