The complex `[Cr(H_(2)O)_(4)Br_(2)]Cl` gives the test for :

Options

A. `Br^(-)`
B. `Cl^(-)`
C. `Cr^(3+)`
D. `Br^(-) and Cl^(-)` both

Answer

To solve the question regarding the complex `[Cr(H₂O)₄Br₂]Cl`, we need to determine which ions it gives a test for. Here’s a step-by-step breakdown of the solution:

### Step 1: Identify the components of the complex
The complex `[Cr(H₂O)₄Br₂]Cl` consists of a cationic part `[Cr(H₂O)₄Br₂]` and an anion `Cl⁻`. The cation contains chromium (Cr), water (H₂O), and bromide (Br) ions.

**Hint:** Look for the cation and anion in the coordination compound to understand its composition.

### Step 2: Determine the dissociation of the complex
When the complex dissociates in solution, it separates into its constituent ions:
- The cation `[Cr(H₂O)₄Br₂]` remains intact and does not dissociate further.
- The anion `Cl⁻` is released into the solution.

**Hint:** Remember that in coordination compounds, the cation often remains as a complex ion while the anions dissociate.

### Step 3: Identify the tests for the ions present
1. **For Cl⁻:** To test for the presence of chloride ions, we can add silver nitrate (AgNO₃) to the solution. If Cl⁻ is present, it will react with AgNO₃ to form a white precipitate of silver chloride (AgCl).
2. **For Br⁻:** Similarly, to test for bromide ions, we can also add AgNO₃. If Br⁻ is present, it will form a cream-colored precipitate of silver bromide (AgBr).
3. **For Cr³⁺:** To test for chromium ions, various methods can be used, but they are not as straightforward as the tests for halides.

**Hint:** Use specific reagents to test for the presence of different ions in the solution.

### Step 4: Conclusion
Since the complex `[Cr(H₂O)₄Br₂]Cl` dissociates to give Cl⁻, and we can confirm its presence using AgNO₃, we conclude that the complex gives a test for Cl⁻.

**Final Answer:** The complex `[Cr(H₂O)₄Br₂]Cl` gives the test for Cl⁻.