Name the gas produced on reaction of dilute sulphuric acid with a metallic sulphide.

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

(1) $\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}

(2) S + 2H₂SO₄ [conc.] ⟶3SO₂ + 2H₂O

(3) $\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}

(4) MgO + H₂SO₄ ⟶ MgSO₄ + H₂O

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

State one appropriate observation for : conc. H₂SO₄ is added to a crystal of hydrated copper sulphate.

In the given equation :

S + 2H₂SO₄ ⟶ 3SO₂ + 2H₂O

Identify the role played by conc. H₂SO₄ i.e.

(A) Non-volatile acid

(B) Oxidising agent

(C) Dehydrating agent

(D) None of the above.