A, B, C and D summarize the properties of sulphuric acid depending on whether it is dilute or concentrated.

A: Typical acid property

B: Non-volatile acid

C: Oxidizing agent

D: Dehydrating agent

Choose the property [A, B, C or D] depending on which is relevant to each of the following:

(i) Preparation of hydrogen chloride gas.

(ii) Preparation of copper sulphate from copper oxide.

(iii) Action of conc. sulphuric acid on sulphur.

(i) B: Non-volatile acid

$\text{NaCl} + \text{H}$2\text{SO}4 [\text{conc.}]\xrightarrow{\lt 200 \degree\text{C}} \text{NaHSO}_\text{4} + \text{HCl}

(ii) A: Typical acid property

CuO + H₂SO₄ (conc.) ⟶ CuSO₄ + H₂O

(iii) C: Oxidizing agent

S + 2H₂SO₄ (conc.) ⟶ 3SO₂ + 2H₂O