A, B, C and D summarize the properties of sulphuric acid depending on whether it is dilute or concentrated. Choose the property (A, B, C or D), depending on which is relevant to each of the preparations (i) to (iv) :
A. Dilute acid (typical acid properties), B. Non-volatile acid, C. Oxidising agent, D. Dehydrating agent
(i) Preparation of hydrogen chloride.
(ii) Preparation of ethene from ethanol
(iii) Preparation of copper sulphate from copper oxide.
(iv) Action of conc. sulphuric acid on sulphur