Which among the following will be named as dibromidobis-(ethylenediamine) chromium (III) bromide?

Options

A. `[Cr(en)_(3)]Br_(3)`
B. `[Cr(en)_(2)Br_(2)]Br`
C. `[Cr(en)Br_(4)]^(-)`
D. `[Cr(en)Br_(2)]Br`

Answer

To solve the question, we need to identify the compound that corresponds to the name "dibromidobis-(ethylenediamine) chromium (III) bromide." Let's break down the name step by step.

### Step-by-Step Solution:

1. **Identify the Components of the Name:**
- "Dibromido" indicates that there are two bromine (Br) atoms in the compound.
- "bis-(ethylenediamine)" indicates that there are two ethylenediamine (en) ligands present.
- "chromium (III)" indicates that chromium is in the +3 oxidation state.
- "bromide" indicates that bromide ions are present outside the coordination complex.

2. **Determine the Coordination Complex:**
- The coordination complex consists of chromium (Cr) and the ligands. Since we have "bis-(ethylenediamine)," we have two ethylenediamine ligands coordinated to the chromium.

3. **Count the Bromine Atoms:**
- The "di-" prefix in "dibromido" indicates that there are two bromine atoms coordinated to the chromium.

4. **Identify the Oxidation State of Chromium:**
- The name specifies "chromium (III)," which means the chromium is in the +3 oxidation state.

5. **Construct the Formula:**
- The overall formula can be constructed as follows:
- Chromium (Cr) with a +3 charge.
- Two ethylenediamine ligands (en).
- Two bromine ions (Br) as ligands.
- Additionally, there may be bromide ions outside the coordination sphere.

6. **Select the Correct Option:**
- From the options provided, we need to find a compound that matches this description:
- It should have two bromine atoms.
- It should have two ethylenediamine ligands.
- It should have chromium in the +3 oxidation state.

7. **Final Answer:**
- After analyzing the options, the correct compound that matches "dibromidobis-(ethylenediamine) chromium (III) bromide" is option B.