A, B, C and D illustrate the properties of sulphuric acid whether dilute or concentrated.
Choose the property (A, B, C, or D) depending on which one is relevant to each of the following:
 Preparation of hydrogen chloride gas. 

Options

A. A = Typical acid property
B. B = Nonvolatile acid
C. C = Oxidising agent
D. D = Dehydrating agent

Answer

To determine the property of sulfuric acid (H₂SO₄) that is relevant to the preparation of hydrogen chloride gas (HCl), we can analyze the properties provided:

1. **Typical Acidic Property**: This refers to the ability of sulfuric acid to donate protons (H⁺ ions) in reactions, but it is not specifically related to the preparation of HCl.

2. **Non-volatile Acid**: This property indicates that sulfuric acid does not easily vaporize. This characteristic is crucial when using sulfuric acid to produce gases like HCl, as it remains in the liquid phase while allowing the volatile HCl gas to be released.

3. **Oxidizing Agent**: While sulfuric acid can act as an oxidizing agent in certain reactions, this property is not directly related to the preparation of HCl.

4. **Dehydrating Agent**: Sulfuric acid is known for its ability to remove water from other substances, but this property does not specifically pertain to the preparation of HCl.

Given these properties, we can conclude that the relevant property for the preparation of hydrogen chloride gas is:

**Answer**: B, Non-volatile acid.

### Step-by-Step Solution:

1. **Identify the Reaction**: The preparation of hydrogen chloride gas involves the reaction of sodium chloride (NaCl) with sulfuric acid (H₂SO₄).

2. **Understand the Role of Sulfuric Acid**: Sulfuric acid is used because it is a non-volatile acid, meaning it will not vaporize during the reaction, allowing the HCl gas to be collected.

3. **Write the Reaction**: The chemical reaction can be represented as:
\[ \text{NaCl (s)} + \text{H}_2\text{SO}_4 (l) \rightarrow \text{NaHSO}_4 (s) + \text{HCl (g)} \]
This shows that solid sodium chloride reacts with liquid sulfuric acid to produce solid sodium bisulfate and gaseous hydrogen chloride.

4. **Conclude the Property**: The non-volatile nature of sulfuric acid ensures that it can effectively facilitate the production of HCl gas without itself evaporating.