JEE Main · 2006 · 30 Apr 2006 · Offline · p-Block Elements

Which of the following chemical reactions depicts the oxidizing behaviour of

H_{2} SO_{4}

(A) $2 HI + H_{2} SO_{4} ⟶ I_{2} + SO_{2} + 2 H_{2} O$ ✓ Correct
(B) $Ca (OH)_{2} + H_{2} SO_{4} ⟶ CaSO_{4} + 2 H_{2} O$
(C) $NaCl + H_{2} SO_{4} ⟶ NaHSO_{4} + HCl$
(D) $2 PCl_{5} + H_{2} SO_{4} ⟶ 2 POCl_{3} + 2 HCl + SO_{2} Cl_{2}$

Answer: (A)

Solution

Sulphuric acid behaves as an oxidising agent only when its own sulphur is reduced. In the change

2HI + H_{2} S O_{4} \to I_{2} + S O_{2} + 2 H_{2} O

, iodide is oxidised to iodine while the sulphur of

H_{2} S O_{4}

drops from the

+ 6

state to

+ 4

S O_{2}

, so the acid is reduced and acts as the oxidiser. In the other reactions it merely neutralises a base or is displaced as a volatile acid, with sulphur staying at

+ 6

throughout. The oxidising role is thus shown by the reaction that converts HI to

I_{2}

JEE Main · 2006 · 30 Apr 2006 · Offline · Single correct option

Practise more: all JEE Main PYQs on p-Block Elements →

JEE Main · 2006 · 30 Apr 2006 · Offline · p-Block Elements

Solution

More JEE Main questions on p-Block Elements