Which is least acidic ? `SbH_(3), PH_(3), NH_(3), AsH_(3)`

Explanation

To determine which of the compounds \( SbH_3, PH_3, NH_3, AsH_3 \) is the least acidic, we can analyze their basicity, as the least acidic compound will be the most basic one. Here’s a step-by-step solution:

### Step 1: Understand the relationship between acidity and basicity
Acidity and basicity are inversely related. A compound that is more basic will be less acidic. Therefore, to find the least acidic compound, we need to identify which one is the most basic.

### Step 2: Identify the trend in basicity
The basic strength of hydrides of group 15 elements (like \( NH_3, PH_3, AsH_3, SbH_3 \)) decreases as we move down the group. This is due to the increase in atomic size and the corresponding decrease in electron density.

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