Other than the X-ray difference , how could be the following pairs of isomers be distinguished from one another by :
`[Cr(NH_(3))_(6)][Cr(NO_(2))_(6)] and [Cr(NH_(3))_(4)(NO_(2))_(2)][Cr(NH_(3))_(2)(NO_(2))_(4)]`

Options

A. cryoscopic method
B. measurement of molar conductance
C. measuring magnetic moment
D. observing their colours.

Explanation

To distinguish between the pairs of isomers `[Cr(NH₃)₆][Cr(NO₂)₆]` and `[Cr(NH₃)₄(NO₂)₂][Cr(NH₃)₂(NO₂)₄]`, we can follow these steps:

### Step 1: Identify the Isomers
The first pair consists of two different complexes:
1. `[Cr(NH₃)₆][Cr(NO₂)₆]`
2. `[Cr(NH₃)₄(NO₂)₂][Cr(NH₃)₂(NO₂)₄]`

### Step 2: Analyze the Ionic Composition
- The first complex `[Cr(NH₃)₆][Cr(NO₂)₆]` contains two chromium ions, one with six ammonia ligands and one with six nitro ligands.
- The second complex `[Cr(NH₃)₄(NO₂)₂][Cr(NH₃)₂(NO₂)₄]` contains two chromium ions, one with four ammonia and two nitro ligands, and the other with two ammonia and four nitro ligands.

### Step 3: Use Molar Conductance
Molar conductance can be used to distinguish these complexes. Molar conductance depends on the number of ions and their charges in solution.

- For `[Cr(NH₃)₆][Cr(NO₂)₆]`, the charge on the complex is +3 for both chromium ions (total charge = +3 + +3 = +6).
- For `[Cr(NH₃)₄(NO₂)₂][Cr(NH₃)₂(NO₂)₄]`, the charge on the first chromium ion is +1 and on the second is also +1 (total charge = +1 + +1 = +2).

### Step 4: Conclusion
Since the total charge and the number of ions differ between the two pairs of isomers, measuring the molar conductance will provide a clear distinction between them.

### Final Answer
The isomers can be distinguished by measuring their molar conductance due to the difference in their ionic charges.

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