The `IUPAC` name for `[AI(OH)(H_(2)O)_(5)]^(2+)` is
(a) Pentahyroaluminium hydroxide
(b) Aquometaaluminate ion
(c ) Pentaaquaaluminate(III)hydroxide
(d) Pentaaquahydroxoaluminium(III) .

Answer

To determine the IUPAC name for the coordination compound \([Al(OH)(H_2O)_5]^{2+}\), we will follow a systematic approach. Here’s the step-by-step solution:

### Step 1: Identify the central metal atom
The central metal atom in the complex is Aluminium (Al).

### Step 2: Identify the ligands
The ligands present in the complex are:
- Hydroxo (OH)
- Aqua (H2O)

### Step 3: Count the number of each ligand
- There is 1 Hydroxo ligand (OH).
- There are 5 Aqua ligands (H2O).

### Step 4: Determine the oxidation state of the central metal atom
Let the oxidation state of Aluminium be \(x\). The overall charge of the complex is \(+2\).

The contribution to the charge is:
- Hydroxo (OH) contributes \(-1\).
- Aqua (H2O) contributes \(0\) (since it is neutral).

Setting up the equation:
\[ x + (-1) + 0 \cdot 5 = +2 \]
\[ x - 1 = 2 \]
\[ x = 3 \]
Thus, the oxidation state of Aluminium is \(+3\).

### Step 5: Write the name of the ligands in alphabetical order
According to IUPAC nomenclature, ligands are named in alphabetical order regardless of the number of each ligand:
- Aqua (for H2O)
- Hydroxo (for OH)

### Step 6: Indicate the number of each ligand
- For 5 Aqua ligands, we use "penta".
- For 1 Hydroxo ligand, we simply use "hydroxo" (no prefix needed).

### Step 7: Combine the names and include the central metal with its oxidation state
Putting it all together:
- The name starts with "penta" for the 5 Aqua ligands.
- Then "hydroxo" for the Hydroxo ligand.
- Followed by the name of the central metal "aluminium".
- Finally, we indicate the oxidation state of Aluminium in parentheses as (III).

Thus, the complete IUPAC name is:
**Pentaaquahydroxoaluminium(III)**

### Step 8: Identify the correct option
Now, we compare this with the given options:
(a) Pentahyroaluminium hydroxide
(b) Aquometaaluminate ion
(c) Pentaaquaaluminate(III)hydroxide
(d) Pentaaquahydroxoaluminium(III)

The correct answer is **(d) Pentaaquahydroxoaluminium(III)**.

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