Which of the following is least stable

Options

A. `NH_4^(+)`
B. `SbH_4^(+)`
C. `PH_4^(+)`
D. `AsH_3^(+)`

Explanation

To determine which of the given hydrides (NH4+, SbH4+, Ph4+, and AsH4) is the least stable, we can analyze the stability of these compounds based on their position in Group 15 of the periodic table and the factors affecting bond stability.

### Step-by-Step Solution:

1. **Identify the Group 15 Elements**:
The elements in Group 15 include nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), and bismuth (Bi). The hydrides we are considering are NH4+ (ammonium), SbH4+ (antimony hydride), Ph4+ (which is not a standard hydride but can be assumed to refer to a hypothetical phosphorus hydride), and AsH4 (arsenic hydride).

2. **Understand Stability Trends in Group 15**:
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