Which of the following metal hydroxide is not soluble in exces of `NH_(3)` solution?

Options

A. `Fe(OH)_(2)`
B. `Ni(OH)_(2)`
C. `Cd(OH)_(2)`
D. `Cu(OH)_(2)`

Explanation

To determine which metal hydroxide is not soluble in excess ammonia solution, we will analyze each of the given metal hydroxides one by one.

### Step 1: Analyze Ferrous Hydroxide (Fe(OH)₂)
- Ferrous hydroxide is known to form a gelatinous precipitate.
- When excess ammonia is added, ferrous hydroxide does not dissolve and remains as a precipitate.
- **Conclusion:** Ferrous hydroxide is **not soluble** in excess ammonia.

### Step 2: Analyze Nickel Hydroxide (Ni(OH)₂)
- Nickel hydroxide reacts with excess ammonia to form a soluble complex.
- The complex formed is [Ni(NH₃)₆]²⁺.
- **Conclusion:** Nickel hydroxide is **soluble** in excess ammonia.

### Step 3: Analyze Cadmium Hydroxide (Cd(OH)₂)
- Cadmium hydroxide also reacts with excess ammonia to form a soluble complex.
- The complex formed is [Cd(NH₃)₄]²⁺.
- **Conclusion:** Cadmium hydroxide is **soluble** in excess ammonia.

### Step 4: Analyze Copper(II) Hydroxide (Cu(OH)₂)
- Copper(II) hydroxide reacts with excess ammonia to form a soluble complex.
- The complex formed is [Cu(NH₃)₄]²⁺.
- **Conclusion:** Copper(II) hydroxide is **soluble** in excess ammonia.

### Final Conclusion:
Among the given metal hydroxides, **ferrous hydroxide (Fe(OH)₂)** is the only one that is **not soluble** in excess ammonia solution.

### Answer:
Ferrous hydroxide (Fe(OH)₂) is not soluble in excess ammonia solution.

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