Hydrogen chloride is formed when sodium chloride is treated with

Options

A. conc. `HNO_(3)`
B. conc. `H_(2)SO_(4)`
C. conc. HCl
D. dil. `HNO_(3)`

Answer

To solve the question "Hydrogen chloride is formed when sodium chloride is treated with," we need to analyze the options provided: concentrated nitric acid, concentrated sulfuric acid, concentrated hydrochloric acid, or dilute nitric acid.

### Step-by-Step Solution:

1. **Identify the Reaction**: We need to determine which acid reacts with sodium chloride (NaCl) to produce hydrogen chloride (HCl).

2. **Consider Each Option**:
- **Concentrated Nitric Acid (HNO3)**: When NaCl is treated with concentrated nitric acid, the reaction produces sodium nitrate (NaNO3) and hydrogen chloride (HCl). This reaction requires concentrated nitric acid (around 55% concentration) and typically occurs at elevated temperatures (around 80 degrees Celsius).
- **Concentrated Sulfuric Acid (H2SO4)**: This acid can also react with NaCl to produce hydrogen chloride gas. The reaction is:
\[ \text{NaCl} + \text{H2SO4} \rightarrow \text{NaHSO4} + \text{HCl} \]
- **Concentrated Hydrochloric Acid (HCl)**: This would not produce additional HCl when mixed with NaCl, as it is the same substance.
- **Dilute Nitric Acid**: This is not strong enough to drive the reaction to produce HCl effectively.

3. **Determine the Correct Answer**:
- From the analysis, both concentrated nitric acid and concentrated sulfuric acid can produce hydrogen chloride when reacting with sodium chloride. However, the question seems to imply a specific reaction that is more commonly referenced, which is with concentrated nitric acid.

4. **Final Answer**: Therefore, the correct answer is **concentrated nitric acid**.