Why `Na_(2)S` cannot be used in place of `H_(2)S` (in presence of `HCl`) as a reagent for `II^(nd)` group cations ?

Explanation

To understand why `Na2S` cannot be used in place of `H2S` (in the presence of `HCl`) as a reagent for `II^(nd)` group cations, we can break down the reasoning step by step.

### Step-by-Step Solution:

1. **Understanding the Role of Reagents**:
- In qualitative analysis, `H2S` is used as a reagent for the precipitation of `II^(nd)` group cations. It reacts with these cations to form insoluble sulfides.

2. **Dissociation of `Na2S`**:
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