Most basic among the following

Options

A. `NH_(3)`
B. `N_(2)H_(4)`
C. `PH_(3)`
D. `P_(2)H_(4)`

Answer

To determine which compound is the most basic among the given options (NH3, N2H4, PH3, P2H4), we can follow these steps:

### Step 1: Identify the Group Elements
The compounds provided contain elements from Group 15 of the periodic table, which includes nitrogen (N) and phosphorus (P).

### Step 2: Understand Basicity Trend in Group 15
As we move down the group from nitrogen to phosphorus, the basicity generally decreases. This is because the electron density around the central atom decreases, leading to a reduced ability to donate a pair of electrons (which is a characteristic of basicity).

### Step 3: Compare Basicity of Nitrogen Compounds
Among the nitrogen compounds, we have:
- NH3 (Ammonia)
- N2H4 (Hydrazine)

To compare their basicity, we note that NH3 is known to be a stronger base than N2H4. This is because NH3 has a lone pair of electrons on the nitrogen atom that can be readily donated, while in N2H4, the electron density is shared between two nitrogen atoms, making it less available for donation.

### Step 4: Compare Basicity of Phosphorus Compounds
Among the phosphorus compounds, we have:
- PH3 (Phosphine)
- P2H4 (Diphosphine)

Phosphine (PH3) is a weak base, and P2H4 is generally even weaker due to the presence of two phosphorus atoms, which reduces the availability of lone pairs for donation.

### Step 5: Final Comparison
Now, we compare the basicity of the strongest nitrogen base (NH3) with the phosphorus bases (PH3 and P2H4). Since NH3 is a stronger base than both PH3 and P2H4, we conclude that NH3 is the most basic among all the given options.

### Conclusion
Thus, the most basic compound among the given options is **NH3** (Ammonia).

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