Which of the following isomers will give white precipitate with `BaCl_2` solution ?

Options

A. `[Co(NH_3)_5SO_4]Br`
B. `[Co(NH_3)_5Br]SO_4`
C. `[Co(NH_3)_4(SO_4)_2]Br`
D. `[Co(NH_3)_4Br(SO_4)]`

Answer

To solve the problem of which isomer will give a white precipitate with BaCl₂ solution, we can follow these steps:

### Step 1: Identify the Compounds
The question provides us with isomers, one of which is [Co(NH₃)₅Br]SO₄. We need to analyze this compound to see if it will react with barium chloride (BaCl₂) to form a precipitate.

### Step 2: Understand the Reaction with BaCl₂
When barium chloride is added to a solution containing sulfate ions (SO₄²⁻), a precipitation reaction occurs, forming barium sulfate (BaSO₄), which is a white precipitate. The reaction can be represented as:
\[ \text{Ba}^{2+} + \text{SO}_4^{2-} \rightarrow \text{BaSO}_4 (s) \]

### Step 3: Ionization of the Compound
The compound [Co(NH₃)₅Br]SO₄ will ionize in solution:
- It will dissociate into [Co(NH₃)₅Br]²⁺ and SO₄²⁻ ions.

### Step 4: Adding BaCl₂ to the Solution
When BaCl₂ is added to the solution, the barium ions (Ba²⁺) will react with the sulfate ions (SO₄²⁻) present in the solution:
\[ \text{Ba}^{2+} + \text{SO}_4^{2-} \rightarrow \text{BaSO}_4 (s) \]

### Step 5: Conclusion
Since BaSO₄ is a white precipitate, we conclude that the compound [Co(NH₃)₅Br]SO₄ will indeed give a white precipitate when BaCl₂ is added due to the formation of BaSO₄.

### Final Answer
The isomer that will give a white precipitate with BaCl₂ solution is **[Co(NH₃)₅Br]SO₄**.

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