With which metal ion, aqueous ammonia reacts to give a deep blue solution?

Options

A. `Ag^oplus`
B. `Mg^(2+)`
C. `Li^oplus`
D. `Cu^(2+)`

Answer

To determine which metal ion reacts with aqueous ammonia to produce a deep blue solution, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Metal Ions**: The question provides four metal ions: Ag⁺ (Silver), Mg²⁺ (Magnesium), Li⁺ (Lithium), and Cu²⁺ (Copper).

2. **Recall the Behavior of Aqueous Ammonia**: Aqueous ammonia (NH₃ in water) can react with certain metal ions to form complexes.

3. **Analyze Each Metal Ion**:
- **Ag⁺ (Silver)**: When silver ions react with ammonia, they form a complex, but it is not deep blue. Instead, it forms a colorless or slightly yellowish solution.
- **Mg²⁺ (Magnesium)**: Magnesium ions do not form a colored complex with ammonia; they typically remain colorless in solution.
- **Li⁺ (Lithium)**: Lithium ions also do not form any colored complex with ammonia and remain colorless.
- **Cu²⁺ (Copper)**: Copper(II) ions are known to form a deep blue complex when reacted with aqueous ammonia.

4. **Write the Reaction for Cu²⁺**: The reaction can be represented as:
\[ \text{Cu}^{2+}_{(aq)} + 4 \text{NH}_3_{(aq)} \rightarrow \text{[Cu(NH}_3\text{)}_4]^{2+}_{(aq)} \]
This complex, \([Cu(NH₃)₄]^{2+}\), is deep blue in color.

5. **Conclusion**: Among the given metal ions, only Cu²⁺ reacts with aqueous ammonia to produce a deep blue solution.

### Final Answer:
The metal ion that reacts with aqueous ammonia to give a deep blue solution is **Cu²⁺ (Copper)**.

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