Question

With reference to the redox properties of hydrogen peroxide $\left(H_2{O}_2\right)$. which of these reactions are feasible?
(i) $2F{e}^{2+}+2H^{+}+H_2{O}_2\to 2F{e}^{3+}+2H_{2}O$
(ii) $2Mn{O}_4^{-}+6H^{+}+5H_2{O}_2\to 2Mn62++8H_{2}O+5O_2$
(iii) $2F{e}^{2+}+H_2{O}_2\to 2F{e}^{3+}+2O{H}^{-}$
(iv) $2Mn{O}_4^{-}+3H_2{O}_2\to 2Mn{O}_2+2H_{2}O+3O_2+2O{H}^{-}$

• A. (i) and (ii) only
• B. (ii) and (iv) only
• C. (i), (ii), (iii) and (iv)
• D. (ii), (iii) and (iv) only

Answer 1

Answer: (C)

$\because H_2{O}_2$ show oxidising as well as reducing action.
Oxidising nature (i.e. act as oxidising agent)
(i) In acidic solution,
$H_2{O}_2+2H^{+}+2e^{-}\to 2H_{2}O$
(ii) In alkaline solution,
$H_2{O}_2+2e^{-}\to 2O{H}^{-}$
Reducing nature (i.e. act as reducing agent)
$\underset{\text{ (n acidic medium) }}{H_2{O}_2}⟶2H^{+}+O_2+2e^{-}$
$\underset{\text{(in alkaline medium)}}{H_2{O}_2+2O{H}^{-}}⟶2H_{2}O+O_2+2e^{-}$