Among the trihalides of nitrogen, which one is the least basic ?

Options

A. `NF_(3)`
B. `NCl_(3)`
C. `NBr_(3)`
D. `NI_(3)`

Explanation

To determine which trihalide of nitrogen is the least basic, we need to analyze the basicity of the nitrogen trihalides: NF3, NCl3, NBr3, and NI3. Here’s a step-by-step breakdown of the reasoning:

### Step 1: Understanding Basicity
Basicity in this context refers to the ability of the nitrogen atom in the trihalides to donate its lone pair of electrons. The more electron density available on the nitrogen atom, the stronger the base.

**Hint:** Remember that basicity is related to the availability of lone pair electrons for bonding.

### Step 2: Electronegativity of Halogens
The halogens (F, Cl, Br, I) have different electronegativities:
- Fluorine (F) is the most electronegative.
- Chlorine (Cl) is less electronegative than fluorine.
- Bromine (Br) is less electronegative than chlorine.
- Iodine (I) is the least electronegative.

**Hint:** Electronegativity affects how much the halogen pulls electron density away from nitrogen.

### Step 3: Effect of Electronegativity on Basicity
In the case of NF3, the highly electronegative fluorine atoms pull electron density away from the nitrogen atom, making the lone pair on nitrogen less available for bonding. This results in lower basicity.

**Hint:** The more electronegative the halogen, the less basic the nitrogen trihalide will be.

### Step 4: Comparing Basicity of Trihalides
- **NF3:** Least basic due to high electronegativity of F.
- **NCl3:** More basic than NF3, as Cl is less electronegative than F.
- **NBr3:** More basic than NCl3, as Br is less electronegative than Cl.
- **NI3:** Most basic, as I is the least electronegative, allowing nitrogen to retain more electron density.

**Hint:** Create a ranking based on electronegativity to determine the order of basicity.

### Step 5: Conclusion
Based on the analysis, NF3 is the least basic among the nitrogen trihalides due to the high electronegativity of fluorine, which significantly reduces the electron density available on nitrogen.

**Final Answer:** The least basic trihalide of nitrogen is **NF3**.