Mercury on heating with aqua regia gives

Explanation

To solve the question "Mercury on heating with aqua regia gives," we can follow these steps:

### Step-by-Step Solution:

1. **Understand Aqua Regia**:
Aqua regia is a highly corrosive mixture of acids, specifically composed of three moles of hydrochloric acid (HCl) and one mole of nitric acid (HNO3). The ratio is typically 3:1 (HCl:HNO3).

2. **Chemical Reaction**:
When aqua regia is heated, it undergoes a reaction. The nitric acid (HNO3) reacts with hydrochloric acid (HCl) to produce several species, including nitrosyl chloride (NOCl), nascent chlorine (Cl), and water (H2O). The reaction can be summarized as:
\[ 3 \text{HCl} + \text{HNO}_3 \rightarrow \text{NOCl} + \text{Cl} + \text{H}_2\text{O} \]

3. **Role of Nascent Chlorine**:
The nascent chlorine produced in the reaction is a powerful oxidizing agent and is capable of reacting with metals, including mercury (Hg).

4. **Reaction with Mercury**:
When mercury is heated in the presence of nascent chlorine, it reacts to form mercuric chloride (HgCl2). The reaction can be represented as:
\[ \text{Hg} + \text{Cl} \rightarrow \text{HgCl}_2 \]

5. **Final Product**:
Therefore, the final product obtained when mercury is heated with aqua regia is mercuric chloride (HgCl2).

### Conclusion:
Mercury on heating with aqua regia gives **HgCl2 (mercuric chloride)**.

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