Name the gas evolved in each of the following cases : Addition of concentrated hydrochloric acid on `Pb_3O_4`

Explanation

To solve the question of what gas is evolved when concentrated hydrochloric acid is added to \( \text{Pb}_3\text{O}_4 \), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**:
- The reactants in this case are concentrated hydrochloric acid (\( \text{HCl} \)) and lead(II,IV) oxide (\( \text{Pb}_3\text{O}_4 \)).

2. **Write the Chemical Reaction**:
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