Hydrogen chloride gas is prepared in the laboratory using concentrated sulphuric acid and sodium chloride. Answer the question that follow based on this reaction :
Name the drying agent not used for drying the gas.

Explanation

To answer the question regarding the drying agent not used for drying hydrogen chloride gas prepared using concentrated sulfuric acid and sodium chloride, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Reaction**:
Hydrogen chloride (HCl) gas is produced by the reaction of sodium chloride (NaCl) with concentrated sulfuric acid (H2SO4). The reaction can be represented as:
\[
\text{NaCl (s)} + \text{H}_2\text{SO}_4 (l) \rightarrow \text{HCl (g)} + \text{NaHSO}_4 (s)
...