Why do we add excess of `NH_(4)Cl` and `NH_(4)OH` in the precipitation of group III cations?

Explanation

To answer the question of why we add excess of \( NH_4Cl \) (ammonium chloride) and \( NH_4OH \) (ammonium hydroxide) in the precipitation of group III cations, we can break down the reasoning into a few key steps:

### Step-by-Step Solution:

1. **Understanding Group III Cations**:
Group III cations in qualitative analysis include metals like Al³⁺, Fe³⁺, and Cr³⁺. These cations can precipitate out of solution under certain conditions.

2. **Role of Ammonium Chloride (\( NH_4Cl \))**:
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