Q28 / 180 · KCET 2018 · Chemistry
\( \mathrm{H}_{2} \mathrm{O}_{2} \) is
- AAn oxidising agent
- BA reducing agent
- Correct answerCBoth oxidising and reducing agent
- DNeither oxidising nor reducing agent
Solution
\( \mathrm{H}_{2} \mathrm{O}_{2} \) can act as both oxidizing as well as reducing agent in both acidic and basic media.
Oxidizing action:
In acidic media,
\( 2 \mathrm{~F} e^{2+}+2 \mathrm{H}^{+}+\mathrm{H}_{2} \mathrm{O}_{2} \rightarrow 2 \mathrm{~F} e^{3+}+2 \mathrm{H}_{2} \mathrm{O} \)
In basic media, \( 2 \mathrm{~F} e^{2+}+\mathrm{H}_{2} \mathrm{O}_{2} \rightarrow 2 \mathrm{~F} e^{3+}+2 \mathrm{OH}^{-} \)
Reducing action:
In acidic media,
\( \mathrm{HOCl}+\mathrm{H}_{2} \mathrm{O}_{2} \rightarrow \mathrm{H}_{3} \mathrm{O}^{+}+\mathrm{Cl}^{-}+\mathrm{O}_{2} \)
In basic media,
\( \mathrm{I}_{2}+\mathrm{H}_{2} \mathrm{O}_{2}+2 \mathrm{OH}^{-} \rightarrow 2 \mathrm{I}^{-}+2 \mathrm{H}_{2} \mathrm{O}+\mathrm{O}_{2} \)
Oxidizing action:
In acidic media,
\( 2 \mathrm{~F} e^{2+}+2 \mathrm{H}^{+}+\mathrm{H}_{2} \mathrm{O}_{2} \rightarrow 2 \mathrm{~F} e^{3+}+2 \mathrm{H}_{2} \mathrm{O} \)
In basic media, \( 2 \mathrm{~F} e^{2+}+\mathrm{H}_{2} \mathrm{O}_{2} \rightarrow 2 \mathrm{~F} e^{3+}+2 \mathrm{OH}^{-} \)
Reducing action:
In acidic media,
\( \mathrm{HOCl}+\mathrm{H}_{2} \mathrm{O}_{2} \rightarrow \mathrm{H}_{3} \mathrm{O}^{+}+\mathrm{Cl}^{-}+\mathrm{O}_{2} \)
In basic media,
\( \mathrm{I}_{2}+\mathrm{H}_{2} \mathrm{O}_{2}+2 \mathrm{OH}^{-} \rightarrow 2 \mathrm{I}^{-}+2 \mathrm{H}_{2} \mathrm{O}+\mathrm{O}_{2} \)
Hence, the correct answer is option: 'C'.