What is a group reagent ?

Explanation

### Step-by-Step Solution:

1. **Definition of Group Reagent**:
- A group reagent is a chemical substance used to identify a specific group of radicals in a mixture. It helps in the qualitative analysis of cations or anions by precipitating them or causing a color change.

2. **Purpose of Group Reagents**:
- Group reagents are employed to separate and identify different groups of ions (cations or anions) based on their chemical behavior. They facilitate the classification of ions into groups for easier analysis.

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