Choose the property of sulphuric acid (A, B, C or D), which is relevant to each of the preparations (i) to (iii) :

A: Dil. acid (typical acid properties)

B: Non-volatile acid

C: Oxidizing agent

D: Dehydrating agent

Preparation of :

(i) HCl

(ii) ethene from ethanol

(iii) copper sulphate from copper oxide.

(i) In preparation of HCl — 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) In preparation of ethene from ethanol — D: Dehydrating agent

C₂H₅OH + H₂SO₄ (conc.) ⟶ C₂H₄ + H₂O

(iii) In preparation of copper sulphate from copper oxide — A: Dil. acid (typical acid properties)

CuO + H₂SO₄ (dil.) ⟶ CuSO₄ + H₂O