Question

The following reactions show the $H_2{O}_2$ behaviour in I and II reactions as:
I. $PbS(s)+4H_2{O}_2(aq)\to PbS{O}_4(s)+4H_{2}O(l)$
II. $HOCl+H_2{O}_2\to H_3{O}^{+}+C{l}^{-}+O_2$

• A. Oxidising in acidic medium and reducing in basic medium
• B. Reducing in acidic-medium and oxidising in basic medium
• C. Oxidising in acidic medium and reducing in acidic medium
• D. Reducing in acidic medium and oxidising in acidic medium

Answer 1

Answer: (C)

Hydrogen peroxide, $H_2{O}_2$ oxidises lead sulphide, $PbS(s)$ to lead sulphate, $PbS{O}_4(s)$ in acidic medium
$\underset{\text{Black}}{PbS(s)}+4H_2{O}_2(aq)\to \underset{\text{white}}{PbS{O}_4(s)}+4H_{2}O(l)$
It reacts with hypochlorous acid, $HOCl$ to produce water, oxygen and hydrochloric acid, showing oxidising action in acidic medium
$HOCl+H_2{O}_2\to H_3{O}^{+}+C{l}^{-}+O_2$