Which is nucleophile

Options

A. `BF_(3)`
B. `NH_(3)`
C. `BeCl_(2)`
D. `H_(2)O`

Explanation

To determine which species is a nucleophile, we can follow these steps:

### Step 1: Define Nucleophile
A nucleophile is a species that has a tendency to donate an electron pair to an electrophile. Nucleophiles are typically electron-rich and can be negatively charged or neutral species with lone pairs of electrons.

### Step 2: Identify Characteristics of Nucleophiles
Nucleophiles usually have:
- A negative charge (anions) or
- Lone pairs of electrons that can be donated to form a bond with an electrophile.

### Step 3: Analyze Given Options
Let’s consider the examples mentioned in the video:
1. **BF3**: Boron trifluoride has a vacant p-orbital and acts as an electrophile because it can accept electrons.
2. **NH3 (Ammonia)**: Ammonia has a lone pair of electrons on the nitrogen atom, which can be donated to an electrophile, making it a nucleophile.
3. **H2**: Hydrogen gas does not have lone pairs or a negative charge, so it is not a nucleophile.

### Step 4: Conclusion
Among the options, **NH3** is the nucleophile because it can donate its lone pair of electrons to an electrophile.

### Final Answer
The nucleophile is **NH3 (Ammonia)**.

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