In the analysis of basic radicals, the group reagent `H_(2)S` gas is generally used in the groups

Options

A. I and II groups
B. II and III groups
C. III and V groups
D. II and IV groups

Answer

To solve the question regarding the use of `H2S` gas in the analysis of basic radicals, we will follow these steps:

### Step 1: Understand the Context
In qualitative analysis, basic radicals (cations) are categorized into different groups based on their solubility and the reagents used for their precipitation. The group reagents help in the systematic identification of these radicals.

### Step 2: Identify the Groups
We need to identify which groups utilize `H2S` as a group reagent. The groups typically considered in qualitative analysis are:

1. Group 1
2. Group 2
3. Group 3
4. Group 4
5. Group 5

### Step 3: Analyze Each Group
- **Group 1**: Uses dilute HCl as a reagent.
- **Group 2**: Uses `H2S` as a reagent.
- **Group 3**: Uses NH4OH as a reagent.
- **Group 4**: Uses `H2S`, NH4OH, or NH4Cl as reagents.
- **Group 5**: Uses NH4OH and NH4Cl as reagents.

### Step 4: Conclusion
From the analysis:
- `H2S` is used in **Group 2** and **Group 4**.

### Final Answer
Thus, the groups in which `H2S` gas is generally used as a group reagent are **Group 2 and Group 4**.

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