Some properties of sulphuric acid are listed below. Choose the role played by sulphuric acid – A, B, C, or D which is responsible for the reactions (i) to (v).

Some role/s may be repeated.

(A) Dilute acid

(B) Dehydrating agent

(C) Non-volatile acid

(D) Oxidising agent

(i) $\text{CuSO}$4.5\text{H}2\text{O} \xrightarrow{\text{Conc. H}2 \text{SO}4} \text{CuSO}4 + 5\text{H}2\text{O}

(ii) S + 2H₂SO₄ [conc.] ⟶3SO₂ + 2H₂O

(iii) $\text{NaNO}_3 + \text{H}_2\text{SO}_4 [\text{conc.}]\xrightarrow{\lt 200 \degree\text{C}} \text{NaHSO}_\text{4} + \text{HNO}_\bold{3}$

(iv) MgO + H₂SO₄ ⟶ MgSO₄ + H₂O

(v) Zn + 2H₂SO₄ [conc.] ⟶ ZnSO₄ + SO₂ + 2H₂O

Copy and complete the following table relating to an important industrial process and it's final output.

Give reasons for the following.

(a) Sulphuric acid forms two types of salts with NaOH.

(b) A piece of wood becomes black when concentrated sulphuric acid is poured on it.

(c) Brisk effervescence is seen when oil of vitriol is added to sodium carbonate.

Why is water not added to concentrated H₂SO₄ in order to dilute it?