The hypothetical complex chloro diaquatriammine cobalt (II) chloride can be represented as

Options

A. `[CoCl(NH_(3))_(3)(H_(2)O)_(2)]Cl_(2)`
B. `[Co(NH_(3))_(3)(H_(2)O)Cl_(3)]`
C. `[Co(NH_(2))_(3)(H_(2)O)_(2)Cl]`
D. `[Co(NH_(3))_(3)(H_(2)O)_(3)]Cl_(3)`

Explanation

To represent the hypothetical complex "chloro diaquatriammine cobalt (II) chloride," we need to follow a systematic approach to understand its composition and structure. Here’s a step-by-step breakdown of how to derive the correct representation of this complex:

### Step 1: Identify the Components
The name "chloro diaquatriammine cobalt (II) chloride" indicates the following:
- **Cobalt (Co)** is the central metal ion.
- **Chloro (Cl)** is a chloride ligand.
- **Diaqua (2 H2O)** indicates two water molecules acting as ligands.
- **Triamine (3 NH3)** indicates three ammonia molecules acting as ligands.
- The overall charge of the complex is +2, as indicated by "(II)".

### Step 2: Write the Formula for the Coordination Complex
From the components identified:
- The central metal ion is cobalt (Co).
- The ligands are:
- 3 ammonia (NH3) ligands
- 2 water (H2O) ligands
- 1 chloride (Cl) ligand

The formula for the coordination complex can be constructed as follows:
\[ \text{[Co(NH}_3\text{)}_3(\text{H}_2\text{O})_2\text{Cl}]}^{2+} \]

### Step 3: Determine the Overall Charge
Next, we need to calculate the overall charge of the coordination entity:
- Ammonia (NH3) is a neutral ligand: 3 NH3 contributes 0 charge.
- Water (H2O) is also a neutral ligand: 2 H2O contributes 0 charge.
- Chloride (Cl) is a negatively charged ligand: 1 Cl contributes -1 charge.

Let the oxidation state of cobalt be \( x \). The overall charge of the complex can be expressed as:
\[ x + 0 + 0 - 1 = +2 \]
This simplifies to:
\[ x - 1 = +2 \]
Thus, solving for \( x \):
\[ x = +3 \]

### Step 4: Write the Complete Formula Including Counter Ions
Since the complex has a +2 charge and is associated with chloride ions (which are negatively charged), we need two chloride ions to balance the charge:
\[ \text{[Co(NH}_3\text{)}_3(\text{H}_2\text{O})_2]^{2+} \text{Cl}_2 \]

### Step 5: Final Representation
The final representation of the complex can be written as:
\[ \text{[Co(NH}_3\text{)}_3(\text{H}_2\text{O})_2]^{2+} \text{Cl}_2 \]

### Conclusion
The hypothetical complex chloro diaquatriammine cobalt (II) chloride can be represented as:
\[ \text{[Co(NH}_3\text{)}_3(\text{H}_2\text{O})_2]^{2+} \text{Cl}_2 \]